soul.justice

So I've been slowly trying to breathe some life back into my bird. My 305 is toast, so I'd mostly been on the lookout for a 350 to drop in it. Well, I came across a 400 sbc instead. It's a 2 bolt main, standard bore. I went ahead and picked it up, guy said no sweat on the money til I get it checked (Machine shop said cleaning and flux would cost $120). As long as she's crack-free, I'm gonna drop it in. Question is, I don't know much about what parts play well in this motor. I DO know that I need 400 heads or drill 350 heads for the steam holes. I got a set of shorty headers from a member here, but I've seen things about starter issues. Will a ccc qjet still play well with this motor? Should I run a stall? I keep getting conflicting opinions on running a stall at the power I'd like to put down, and tbh I personally don't know enough about it to make a decision, the strongest-running car I ever owned was an 06 Grand Prix with an LS4 (303 HP isn't meant to go through the front wheels, ate wheel bearings for breakfast ) And what about accessories, do I need to tap holes for certain things?

I'm looking for 300 hp/400 tq at the wheels (or in the area), redline @ 5500 or thereabouts. I want this done right, but don't want to spend a fortune- aluminum heads arent in my future. No tracks around here so she'll be all street. 3.08 rear gears behind a 700R. I don't usually get on the skinny pedal, but when I do I like to leave rubber (stay fast my friends). I've got all the tools to do it and there are several machine shops to choose from around here for decking/honing/etc.

Help a second-time rebuilder out.

Edit: Went and checked cyl bore, its standard size according to the internet. Idk why I thought it was .040 over.

five7kid

iTrader: (14)

Factory 400 heads are about the worst thing out there. Large chambers, rotten flow, crack prone. Just drill the heads you get for the steam holes.

For a 5500 RPM street engine, a set of Vortec heads would work fine.

If you want to use the CC q-jet, then this kit would get you the heads, rockers, bolts, and intake (you'd probably need to get 400 head gaskets for the steam holes): https://sdparts.com/details/scoggin-...nter/sd8060kit

You should probably assume dished pistons to keep compression reasonable. And don't bore it any more than necessary - .010" over if possible.

A mild cam like a Comp XE268 would easily make 400 HP at the crank without breathing hard.

You can get an external balance, 2-piece rear main seal, 153-tooth flexplate and solve that issue. But, you may need to drill/tap/ream a starter bolt hole if your block only has 2 starter mount bolt holes.

If the headers aren't at least 1-5/8" primaries, you'll be choking the poor engine.

Yes. A torque converter that doesn't stall is not a good thing.

Okay, upgrade the torque converter. A 2000 stall should be fine.

Shouldn't have to. Except possibly for the starter as mentioned above.

soul.justice

My guesstimating on the stall wasnt that far off then, I assumed I'd need a 2500 stall. I was told by several people that a factory converter would be fine but I had a hard time believing that. The only other motor swap I've done was with a buddy on his foxbody, and he had a stick. Hence I dont know much about stalls.

I think I'm gonna stay standard bore, the cyl walls look super clean but if I absolutely have to bore them I hope it won't take more than .020 as I don't want the walls flexing, there isn't much meat there to begin with anyway. And I will go out and check the tubes on the headers but I'm pretty sure they're at least 1 5/8.

I can get a set of 062 vortec heads for $150 from a friend of mine, they've been checked out good and hes got papers on em. I've been told 906's flow better but I've poked around on the internet for a set and I'm just not paying that for used heads. And what about splaying the main caps? Should I bother with it or leave it be since I'm not going to be turning (relatively) high RPMs?

Finally, what about my exhaust system. It's 3" or close (definitely not less than 3") to the muffler, then it's two out to the rear with a high-flow cat. Should that be sufficient or would I want to get it reworked as well? This may be a moot question anyway as when I go to weld SFCs in if the current routing is in the way it's gonna have to go regardless but I'd like to save a nickel where I can without shooting myself in the foot.

five7kid

iTrader: (14)

The only difference between 062 and 906 was the casting method. They perform identically. Stock Vortec springs are junk with any kind of upgrade cam, and the valve guide OD is too large for the typical SBC upgrade spring. People either use beehive springs, or have the guides cut for better springs and positive-type valve stem seals.

3" exhaust should be okay. Single-in, dual-out crossflow mufflers aren't all that great, but should be adequate.

abray1

The 400 has siamesed cylinders and water cannot flow between the cylinders and therefore cannot get rid of heat as easy. You will need to look at a good radiator and I always like to get a good high flowing aluminum water pump. The best design radiators have 2 rows of tubes that are 1 inch wide (each tube). Two bottles of water wetter or two bottles of purple ice will help 12-15 degrees. Go ahead and drill the starter hole now since Myself and others have had starter trouble with the stagger mounted starter bolts forever. These are just some of the things I have run into and seen many times myself. I also converted to an internaly balanced rotating assembly to get rid of the weird harmonic balancer and damper. The torque they make is great and you can get a small stroker crank and bore it a little and get big block cubic inches.

1gary

Explain the conversion to internal balance.

soul.justice

Got the block fluxed. Everything checks out except there is a hairline crack on the outer ring surface where the oil filter adapter bolts to. It is not cracked through and the crack is maybe an inch from end to end. I'd like a second opinion, so is this something that can be safely brazed/welded/stitched? The guy doing the work for me said that the way it is cracked there's no way it happened while the engine was in service, something had to have hit it or been dropped on it the right way since the crack is beveled out and away from the rest of the surface.

midias

A lot of 400 guys like these on their high torque mild builds

http://www.jegs.com/i/ProMaxx-Perfor.../2151/10002/-1

They are basically clones of the bowtie vortecs. Just drill them for steam holes.

Post a picture of the crack it could be welded or stitched depending on where it is.

soul.justice

here are two pictures of the crack







The crack does not extend any further than 1/16" into the mating surface. I'm pretty sure it could be grinded out, brazed, and machined flat with zero issues. I also have another question about cooling- will the stock setup (plus larger radiator) be sufficient, as in fan shroud+air dam+regular ol' water pump?

I'm picking up a bare set of vortecs tomorrow afternoon as well. Excited to finally get something going with my swap. I need to get the 305 yanked out and take it to the scrap yard so I'll have beer money this weekend...

SouthSide2

I would take a hammer and break that chunk clean off. Then build up the sur
face that the "filter seal" seals against by weld or braze/silver solder. I would grind the weld/braze with hand power tools to make a good surface for the seal. No machine required if done with skill.

1gary

I do think a honest evaluation is a question of do you want to chase risk with dollars to try to fix this when it is not the last 400 on earth.A round about figure of a build up on a 400 with decent heads is all of $3,500 or more only to lose it all if the repair doesn't hold.

sofakingdom

iTrader: (1)

No need to "repair" that crack at all, if the filter sealing surface is undamaged.

I ran a 400 for around a decade and a half in my 83. Stock radiator, stock single electric fan, Stewart water pump, A/C working and used continuously, in the deep South. All duct work intact. (all the pieces between the headlights & rad, lower air dam, etc.)

soul.justice

The crack does not extend to the inside of the mating surface. I am taking it to another shop Tuesday for another opinion, though, as I agree that I don't need to set my money on fire.

You're right its not the only 400 block but they command a large premium where I live and its about impossible to find one that hasn't been tampered with in some way or had the **** beat out of it on a dirt track.

Got the vortec heads today as well. Now I just need to find a standard crank that doesn't cost an arm and a leg...

SouthSide2

I took a look at a 400 block today and saw something interesting about the same area as your cracked area. It looks like a invest/vent/gating (or a spot where the molten iron was fed or vented). This extra metal is broke off or ground off at the foundry. So it may have been done at the factory. As it did not (the gating) brake away cleanly from the block as it was supposed to.
My thought is it has been there from the beginning. As a factory goof/it's OK ship it.
So look at it carefully.
I too am building a 400 SBC and reading all I can. I think we want the same type of build. Loads of torque, HP done at 5,500 rpm or less. Oh yeah... pump gas!
I have my car totally apart. Working at it as time permits. So many engine parts are still under scrutiny.
I have committed to 9:1cr so as to use a mild type cam that can pull to 5,500

1gary

Work from the foundation first.That being the block.Game plans change all the time in the course of a build.Nothing wrong with that,actually pretty smart.

Gotta wonder if as the block goes in time heat cycles,if that crack wouldn't open up.If it is a question of it coming from GM that way,be very sure it was run tested and didn't leak then.I know because I was one of the guys that did that.

But in the same hand your dealing with in all honestly a antique engine that is very old that needs now matter what a sonic check,mag'ed,bore and or honed with torque plates.Cracks are commonly found from the steam holes out.

The stock short 400 rods makes it into a smog turd with any head that has poor quench numbers turning it into a detonation issue.And heads that have a intake runner no smaller the 195CC's.Nope,the stock Vortec's can't be made to run that big and C.I. size dictates how big you need.

But again as I said,work from the block out insuring you have good one to work with.

sofakingdom

iTrader: (1)

That crack in that block is impact damage; looks like it got dropped on concrete; you can see the imprint easily enough. Didn't come from GM like that, nothing to worry about there.

I'd run it in a heartbeat if everything else about it is OK (walls good, not too many cracks around the head bolt holes, none of The Problems from crappy 70s machining and QC like the starter too far from the crank or the lifter bores not pointed at the cam or the BH dowel pins not so far off that offset ones won't fix it, etc.) AND IF the oil filter pad sealing surface is undamaged.

soul.justice

Anybody have good experience with scat cranks off eBay?

sofakingdom

iTrader: (1)

What does ebay have to do with it?

That is, are you asking if being sold on ebay "transforms" cranks in some way, compared to other sales channels?

ebay is merely a venue for sellers to sell. There are some good and some bad. For the most part, items on there with brand names, factory packaging, etc. are the same as the same item in any other sales venue. Unfortunately there are also crooks, who get hold of stolen merchandise, factory rejects, counterfeits, etc. and sell them without disclosing any of that. Cyberspace is no different from meatspace. Would you buy a crank from a guy walking down the sidewalk that opens his jacket and flashes rows of them in his inside lining? No different on ebay. Evaluate individual sellers, not "ebay".

1gary

I hate to be like this,but what have you done to the block other than look at it??.You can buy any parts you like to bolt to it,but if it is a flawed block,it will come back to bite you in the butt and do-overs cost alot more.

Follow the suggestions the are geared towards 400's specially.

soul.justice

I had it magnafluxed, and that's about it. Everything is acceptable according to the guy at the machine shop except the aforementioned crack at the oil filter mount and as I said he told me it doesn't extend into where the seal would be.

As for my question, sofa, I am doing this on a working man's budget. I want it done right, and well, with good parts, but also save a nickel where I can. I don't have the funds in this project to spend $500 on a crankshaft or $1200 on heads. Thus if the risk of buying something off eBay and getting junk is too large in other members opinions then I need to buy elsewhere, but obviously eBay is the cheapest avenue, which is why I looked there first. I know there's always a risk if you're not buying from an established company, but those same companies come with a premium tacked on to their prices. If I had an $8000 budget I'd just buy everything from Summit/Jegs/whoever but seeing as I dont I have to look at every part and see if I can get it cheaper somewhere else. Cheap doesn't always mean bad quality, but with eBay, sometimes it does. I was hoping for someone to chime in with a "I bought from such and such seller and received a good product" or similar.

If there is somewhere else I can buy parts that doesn't command such a premium price for things I am very open to suggestions. That's why I'm here asking questions after all

1gary

Oil passages:



Big question is IF the crack goes to the passage??.

soul.justice

I was told by the guy who did the magnafluxing that it was not a big deal and that he felt in his opinion I shouldn't worry about it. I don't see how it could extend into the oil passage seeing as its on the very outside of the filter boss and it looks like a clean break, like the chunk would fall off and that would be the end of it. Now if the crack extended into the mounting surface itself where the filter will seal against the block I would be concerned and would've already found another block to use.


What else could I do to assure its of no concern other than spending $2000 on a dart block

1gary

There is in no way shape or form I'm suggesting a Dart block.In castings like on engine blocks,cracks will migrate or spread with heat cycles.There is a process to stop that with cast iron.The only one I knew of is in Boston,Mass is a shop known for their cast iron welding.High skill level and talent.Excellent success rate.

I do think it is very important you follow the steps outlined for all 400's in prep machining and testing.Maybe sonic check the crack too.

soul.justice

I contacted another local shop and explained the situation and my concern for this crack. I have heard many good things about them and I went out of my way to specifically ask about cast iron brazing when fishing for opinions among my elder gearhead friends. I am taking it next week to have it mic'd and repaired if necessary and possible. I am keeping my parts purchasing for now to things I can use in a smaller displacement motor if need be until I am sure I can use this block. I'll update in a week or so.

abray1

If the rubber part of the filter is not affected in sealing area then It should be fine. I got a 400 years ago and half the starter block area was cracked. My last 400 I got a scat internal balanced crank, rods and pistons and it has been great.

1gary

I think that is a very good move on your part.Do let us know how it works out.

soul.justice

Lets talk about heads. Would it be worth the while to have them machined for larger valves or should I keep them as is? I've read a lot of conflicting reports on doing this with vortec heads. Also would I want to get new valves even if keeping with stock spec valves? They look pristine.

1gary

Vortec Bowtie Cylinder Head Technical Notes: • Cast-iron small runner or large runner cylinder heads*
• 66cc combustion chambers
• 0.450" deck thickness
• Hardened exhaust valve seats
• Machined for 2.000"/1.550" valves
• Maximum 0.530" valve lift (without modifications)
• Straight spark plug design
• No heat risers
• Drilled and tapped for 7/16"-14 screw-in studs
• Dual bolt patterns for Vortec and early style intake manifolds (early
model P/N 10051103; Vortec intakes P/N 12366573,12496820,
12496821, 12496822 or 12489371)
• Use intake gasket P/N 12529094 for Vortec intakes or dual pattern
intake gasket P/N 12497760 for early model intakes or Vortec design
intake manifolds
• Dual bolt patterns for perimeter-style and center-bolt valve covers
• Vortec intake manifold three-step torque specs: 2 lb.-ft.; 9 lb.-ft.; 11 lb.-ft.
B. 25534421
Small Port Vortec Bowtie Cylinder Head Assembly
• Completely assembled, ready to bolt on
• 185cc intake ports
• 65cc exhaust ports
• Use Fel-Pro® P/N 1470 exhaust gasket
• Bare head P/N 25534351, available separately
25534446
Large Port Vortec Bowtie Head Assembly (not shown)
• Completely assembled, ready to bolt-on
• Improved air flow (281 cfm @ 0.600")
• 225cc intake ports
• 77cc exhaust ports
• 65cc combustion chambers
• Use Fel-Pro® P/N 1470 exhaust gasket (minor trimming may
be necessary)
• Bare head P/N 25534445, available separate

1gary

As you can see there is two port sizes.The smaller one for basically a 350/355 or a torquer 383/400.The larger one for a high RPM 350/355 or a larger 383/400 moving the power curve up.

SouthSide2

Here's a few pics of large port vortec bowtie heads part# 25534446. The gasket show is from a 1990 305. The exhaust port is taller too by about an 1/8" over stock/standard.
I choose these heads for my 400 build. Really every thing I wanted. I will disassemble to inspect them. Checking valves are seating correctly, also insure there some oil in the guilds for start up. May smooth a sharp edge or two, just a slight polish.

My thoughts are going bigger on the heads with 400 cid from the start insures that the engine can run to 5,500 rpm or more. Letting the cam control rpm range. The down side of going bigger seems to be a slight lost of power at lower rpms. This engine is all ready going to make more power than the 305 at lower rpms. So I'm sure I would not miss it.

soul.justice

If I use an LS-type beehive spring I do not have to have the valve guides cut, correct? Are there any benefits or caveats with doing this as opposed to having them cut and using a typical SBC spring? Should a 3 angle valve job be sufficient? Also, from what I understand CCC qjets flow 650 cfm from the factory. Will this still be sufficient? Rejetting/new hangers? I rebuilt it about a year ago so its in fantastic shape now.

Thanks for the info on the vortec heads. I'll probably just use stock size valves as I don't really see much benefit with going with 2.02/1.6's for the flow vs money I'd spend to do it.

Last question for the day- what size connecting rods? I-beam vs H-beam? I understand there are two different sizes to use with the 400. I am sticking with a stock crank.

Sorry if my questions are redundant or obvious. I have done a stock spec rebuild on a 4.3 V6 before and that's it, I know almost nothing of the performance aspect of building motors. I appreciate yalls patience and time.

SouthSide2

Here a pic of a 400 block that looks close to yours

1gary

Scat 5.7 rod for a 3.75 stroke with the pistons to match.

SouthSide2

5.7 scat rod is smart (I beam, 7/16 bolts). Pistons are next on the chopping block.
Check out KB pistons/uniteted engine biulders website. Good info there.

Compression ratio should be high on the what's next list.
64/65 cc vortex heads? What should any one do in your shoes.
Five7kid and 1gary could put a fine point on this.

1gary

My favorite pistons is the "D" style which can give you the quench numbers you want at a SCR for pump gas.

SouthSide2

Good thread... happy to see a update.

soul.justice

Update on block work.

Had it sonic checked. The crack is not an issue and does not interfere with any critical oiling systems, or anything really. The guy is still going to break the chunk off and braze new material in anyway (at my request). Block will be bored .030 to take care of some cylinder wall scoring. My heads were warped .005, they will be taking care of that as well. Crank is going to be ground and polished but is otherwise fine(stock 400 crank I got for dirt cheap). I'm not sure if I'm going to go with 5.7 or 6" rods. I keep hearing conflicting opinions. Heads are getting drilled for steam holes and I'm having them tap another hole for the starter.

In summary looks like I'm a go for using this block.

sofakingdom

iTrader: (1)

There is very little benefit to lengthening the rods, other than allowing internal balance. "More" is "better", of course; no dispute there; the question REALLY is, HOW MUCH "better", and are the down sides (rings must be narrower, spaced tighter, closer to the crown, pass through the pin bore, or some combination of all of the above) worth the minimal gain.



I'd also suggest that you investigate the price and availability of pistons in a suitable configuration to match the various rod lengths, BEFORE purchasing rods.

Since you are running a stock crank (not a good idea IMO but W/E) you already cannot internally balance it, you are stuck with external balance.

Therefore I'd suggest using 5.7" rods, except of course NOT stock ones, because that will require a HUGE amount of clearance work and possibly a small base circle cam. Especially since this is going to be such a short-stroke (3.75") motor.



This is a stock "X" rod vs an Eagle cap-screw rod. Any other brand will be of similar dimensions so don't get too hung up on that.

Which one do you suppose will fit inside the block better?

1gary

Now that is good news and good to know,isn't it??. The sonic check I hope was done on the deck and bores too because this is a thin wall/deck block.When you say the heads are warped,does that also mean the deck was warped also??. That is normally the case. If it is going to be decked and squared to the crank center line,how much it going to take??. That will impact which piston/rod combo you use for pump gas SCR and quench numbers which is important to the build. Also what chamber volume of the heads will be. The DCR which takes into consideration which cam to choose is also apart of the build. This is the core of a "matched" parts build. It isn't so much the gain solely by rod length alone but how those choices effects the big picture of everything else. Prime example is the short 400 rods being used on a non-decked block resulting in pistons too far down in the bore and having poor quench numbers which ignores how good quench numbers is a tool to be anti detonation. It also ignores the primary reason for using a larger 400 in the first place. Building somewhat of a turd engine that doesn't capitalize the advantage of the 400. A 5.7 stroker clearanced rod will help in cam choices not needing a small base circle cam. Here is the Scat 5.7 rods that are stroker clearanced:




And some pistons which are made for a 5.7 rod which are made to provide good SCR's and good quench numbers while using pump gas:




None of this is high end parts.It's just good build planning.You see built into the piston is a dish and a quench ring. Kind of the best of both worlds if applied correctly. Lastly,in my opinion,the longer 5.7 rod is important to a 400 because it provides less thrust on the bore of a thin wall 400 block.

While I'm on the topic of 400's being a thin wall bore, torque plates need to be used while any boring/honing is done with the pistons in the hands of the machine shop to for finished size.Those torque plates simulate what it is like having heads torqued to the block for a good seal of the rings.See the bores on a 400 being thin walls do move around once torquing heads to the block.


Sofa-see my post.

soul.justice

I am going to the shop tomorrow to discuss options on pistons and rods, although I will be taking y'alls advice on using aftermarket sourced 5.7" rods. I wasn't able to speak with the guy who is doing the work on the block as he wasn't in when I called but I'll know how much of everything has been shaved when I go there tomorrow, and I will appreciate y'all's advice and input on this as with everything else.

Sofa, why do you feel a stock crank is a bad idea? I do fully agree though that stock rods are a terrible idea and that was made pretty clear to me when I first started looking around for a 400 block to begin with so no argument there. Is it purely because of the stroke? I didn't think I was shooting myself in the foot when getting it.

sofakingdom

iTrader: (1)

Mostly from breaking too many of em. Too much stress at the snout. They break either where the front of the #1-2 throw meets the snout, or where that throw meets the rod pin. They CANNOT withstand any significant RPM for any significant length of time. Anything over about 5500 on a regular basis, you better have a spare in stock.

One I broke, still ran; drove it home and into the garage in 2 pieces. Made lots of noise, didn't run "right", but ran. The others, not so lucky.

fireburdluvr85

Have to agree with the stock crank. Mine broke the snout off while I was cruising to work. That was not fun...

soul.justice

Sorry I haven't updated been busy with preop counseling for a surgery my fiancee is having and working ridiculous overtime.

So based on what the shop guys told me and much lengthy discussion we decided to do 5.7 stroker rods as yall advised and went with Keith Black 168 pistons. They're also doing a 5 angle valve job for an additional $75 a head. I'm going to pick up the motor next week at which point ill do the rest i.e. Rockers, cam, intake, etc etc

Now i have to consider brake upgrades and etc... I'll be able to go, but it wont do me any good if i cant stop what else would you guys suggest I do? I'm going to drop the tank soon and siphon off old gas and clean it when I do the SFCs, will I still be fine with a mechanical fuel pump?

rb89gta

Well soul.justice, I just bought my ta. & am building a 409 sbc ( it's a high nickel block. .040 over & most people call it a 408, but when you do the math it's 408.7ci ), THIS IS NOT MY FIRST .040 build, I absolutely love the combo!
With that being said, I am running a Scat 9000 series internal balanced crank, scat 4130 "I" beam rods floating pins, flat top 2 valve relief probe forged pistons, moly rings, good balancer and fly wheel ( going with a 6 speed tranny ), schuman dual feed oil pump, one piece oil pump drive shaft, canton rr oil pan, pro gear billet timing set w/torington bearing, comp cams solid roller, lunati pop-up lifters, dart pro 1 215 cc runner 64cc chamber aluminium heads, single plain. raised plenum intake and a 850 double pumper.
if you have a solid block, high flow water pump, good aluminium radiator & good ignition system ... you won't have any problem with a .030-.040. 400

rb89gta

BTW, my compression will be 11.5:1 & running on pump gas

1gary

Quench numbers??. DCR???

rb89gta

Not sure about your. abbreviations SCR OR DCR?
I am running an exact fit bore gasket. with a compressed height of .045 (MLS / FEL-PRO)
A 6" rod w/ piston compression height is 1.140, it leaves the piston .010 in the hole
the chambers in the heads are/ will still be 64 cc's ( after HVH is done unshrouding the valves a milling them back to 64)
Also stepping up to 2.08 intake valves, from. 2.05 as well as gasket matching the runners to a 1207
I hope this answers your questions, if not ... ask again in plain language, as I am probably older than most newbies and not hip to the text lingo

rb89gta

I figured that, since I am telling you everything about my build .. you might be interested in some clearances as well :
Piston to valve will be no less than .100
Rod to cam .060-.080
Rod to pan rail .060 or better
thrust .004
Rod bearing. .002-.0025
Mains .0022-.003
Lash .018/.020

sofakingdom

iTrader: (1)

How about, ACTUAL MEASURED top of piston below top of deck? (i.e. how far "down in the hole" are they @ TDC, REALLY TRULY ACTUALLY) Just for Ss & Gs, PHYSICALLY MEASURE all 8 with a straight-edge and a feeler gauge (NOT "the catalog says", NOT "I assume", NOT "I calculate", or similar: MEASURE) and post what you get.

rb89gta

First of all, I have ... some parts physically, I have some parts in route . I do believe that I mentioned, that this is the engine I am BUILDING, not built . SECOND, I am not a kid, a bench top / catalog racer . When I say or give a range, that is where I set my engines up at, or no less / more than I say i.e.( mill, surface after using a DIAL INDICATOR mounted in a magnetic base. after block has been bored with in .002 of it's finished point . that is so the block will accept the rotating assembly with out rings on the pistons. you don't break rings, or ring lands & you get a true reading on both, the top and bottom of each piston, add the together, divide by 2, and then you know what you have and where you need to go. So,