DeltaElite121

This is probably one of the best statements I've seen you say on this forum. Too often people get caught up on some magical "600 horsepower budget build SoOooO EZ 2 do" build when in all reality it costs a hell of a lot more than that.

OP - If you decide to go with a flat tappet, I only recommend a solid flat tappet for the extra benefits, and only if you're willing to use high dollar lifters on an upgraded cam core. Hydraulic flat tappets are worthless and offer no benefits whatsoever compared to either direction (solid flat or hydraulic roller).

SouthSide2

Well like sofa said your vortec heads are better than the stock heads of the era. Have a peace of mind!... you have the best head on the cheap. His cam example is a good example. How ever... You could go smaller on the cam to avoid fixing the lift limit of these heads. Still should use new springs. IMO.

If quench factor is truly important as I believe..You must get a .040 /.055. Number. Which means decking the block. Your machine guy may not know you are building a better newer smarter engine. That requires a different apporch. (Is this a speed shop??) Which means more money. I think this action( good quench) is the key to power and should be of great importance.

When you have the real numbers as what you have for quench and SCR Then its
time to talk. Cam.

This could take a bit longer than you thought to get running .

I like the fact you place your wife is first. A good wife is better than a car will ever be! You can quote my on that.

1gary

And the Bowtie large port heads mate up better with a 400 than the OEM production heads.

rb89gta

Well SJ, i am trying to get some pictures to load on here but my phone service in the area sucks! I will get it sorted out . They are of another 406 that I am building for one of my best friends . it's goin into a 73' Stingray for street /strip duties . but the combo is similar to my engine ( gotta get his done first ), it's. a 6.125" rod, 2 valve relief flat top forged piston, forged crank, solid roller cam & lifter, aluminium headed, 11.63:1 SCR ( w/ 11.11 DCR )pump gas 406 sbc.
if you have the large valve vortec heads, they will do just fine for the power level you are shooting for ( probably a little more ), I also believe I recommended running a hyd. roller cam.... so, I have to agree with at least the idea of what others have said .
I have told many people, that I would rather it take longer to build an engine ( due to $$, and waiting to buy the rite parts. ), than have to tear it back apart to clean and fix it again, or start over because there is nothing left?!
take your time, save your $$$ & shop smart ... you'll be much happier in the end

soul.justice

As much as I love owning a third gen, I can't have sex with it.



I'm waiting on a new crank and stroker rods to come in so I can assemble everything and he can get a true measurement on tdc and deck height and go from there. As far as I know right now aside from the boring he did this is a virgin block and the deck has never been touched. Time is not really an issue for me. I'm willing to wait and spend the money so this is done right. I'm trying to get t running by December but if it takes longer, so be it...but I don't see a reason why it would.

1gary

Question.How are you using a 6.125 rod on 3.75 stroke and a OEM 9.025 block with flat top pistons only to end up with 11.63 SCR??..Is this a aftermarket tall deck block??.

Just trying to get the same answer??.

1gary

A easy way to tell if the block has been decked before is if the stamped numbers on the passenger side front of the deck are missing,then it was decked.

soul.justice

Can someone describe or point me to a resource on getting this other starter hole drilled? Or do I just buy x starter and use it for my template?

I have decided to sell the used crank and use a Scat internal balanced crank. Its not much more for it and I can get rid of the used crank easy since everyone around here wants to build 383's. This will keep me in line with my goal of using as many new parts as is economically possible.

What are the benefits to running a front vs rear sump pan? I would say rear myself.

1gary

It's important for you to understand that if your going for a internal balance,you need to buy the internal balance rotating assembly complete.(crank,rods, the correct pistons for your set up,rings,rod bearings,piston pins)Not just a crank.Even some of those will need to be balanced we have found.That could get expensive.If you find your backed into a corner on the cost of balancing,ask your machinist if you could use a balance plate to bolt to the back of your crank making it a neutral balance.It is a cheap way out that works.

soul.justice

Thanks for the explanation. Being that I already bought KB pistons i may just stick with an external balance crank and just buy a new one.

sofakingdom

iTrader: (1)

Starter bolt hole looks like this:



Unfortunately I didn't record the dimensions when I did that particular 400 block, about 25 yrs ago. But as you can see, it's a "special"-ish hole; there's a "shoulder" section for the bolt that's about ½" deep, before you get to the threads.

If the block has yet to go to the machine shop, just have them do it for you; shouldn't be much $$$ at all, and avoids the risk of screwing it up somehow. Just tell em you want them to add the inboard hole for the starter for the 12.8" (153-tooth) flywheel.

SouthSide2

I have seen a jig you could buy to drill the hole exactly , (just more $) If you have good eye /hand skills you could do this your self. I drill and tap holes all most everyday on my job, which I have 25 years experience. There are many ways to get it right.And a bunch of ways to get it wrong. I would have a expert do this... Unless you are a expert. A wise man told me "make sure you are right and go ahead".

SouthSide2

I'm working on a way to use a stock type roller cam in our old block. It involves some special relocation of the stock retainer. More to come on this.

1gary

rb89gta

SJ. the rods and pistons will be the same for an int. or ext. balance . the machine shop will have to have them to measure their weights so they can balance the crank. i.e. bob weight .
I would recommend paying for the balance work over the plate , the plate adds more weight ... not helping you at all in the RPM area . Don't get me wrong, they work ok just unnecessary for the cost difference . your machine shop, should be able to balance a standard flex plate and balancer with your rotating assembly

rb89gta

Just curious, what exactly is your rotating assembly comprised of? I know you are getting the Scat crank ( they are as nice a piece as your goin to get in a cast crank and a hella lot better than stock ). But which rods and pistons, balancer and flex plate?

rb89gta

SJ, if you would like to see a bit of what I do ... check out my album ( finally got my phone to download pictures )

1gary

If Mallory metal is needed,the expense of internal balance adds up quick.Most places just to set up spinning the crank is $250.Not uncommon to end up seeing a range from $600 to $850 to add what is needed in Mallory metal.As I stated,the plates are not nearly as expensive. For your use the plate is a non-issue.

Guys all the time talk about mixing and matching parts,but find out in the end to put it together can be costly. And those lower dollar rotating assembly's balance are very questionable where they end up needed to be balanced anyways.

BTW-companies come up with terms like "cast steel" in crankshafts that no metallurgist has ever hear of before.It certainly is a spin tactic to try to create sales.Best to stick to the terms of cast is cast and forged is forged.

1gary

Hope you can clarify.

sofakingdom

iTrader: (1)

Cast steel = investment casting; basically they take powdered steel, put it in a mold, and melt it. Depending on what the base metal is, you can make some REALLY good parts that way, that aren't practical to forge for any number of reasons. You can also make some total crap if your objective is simply "lowest possible cost for something that can legally still be called steel". Most of the "cast steel" cranks are somewhere in between, closer to the latter than the former, since there's no particular constraints on forging, that affect cranks very much.

This rb guy is pretty much a waste of time; seems to be a bunch of hot air that just wants to be a blowhard about how great he is. Mostly just diverts s.j's thread off into the weeds with his "lookie me and my laws of physics rewriting motor" spank-off. I don't see any point in engaging him in conversation myself, so I avoid him. I'd encourage you to do the same.

airblaine

so for a 400 that's externally balanced, there is a specific balancer and fllywheel. they are 168 tooth flywheel, staggered bolt pattern starter, and of course the eternally balanced harmonic balancer.
if he drills the extra hole for the 305-350 SBC starter then what flywheel and balancer is he using?
a 153 tooth external balanced flywheel and the same external harmonic balancer or something different?
basically what i am asking is doesn't the harmonic balancer and the flywheel have to compliment each other?

SouthSide2

Look close.

SouthSide2

I was going add the new starter bolt hole by hand... but why if I'm putting it in the mill for cam retainer holes. I also added the neat little cast iron adapter. To change the dip stick to the other side. This requires the oil pan from a 1985 engine with 2 piece rear main seal.
The cam retainer is rotated 20 degrees. I spotted two holes flat with a "end mill". I made spacers out of 1/2" steel round stock. All I need now is two 1/4-20 X 1" low head cap screws.

SouthSide2

This work was a joint effort of the company I work for (allowing me to use the shop. And my brother who helped me lift/roll this block from trunk to mill to trunk. All I'm saying is I'm fortunate to have the resources to do this work. There are many ways to do this with out a machine/mill. It's just going to take a lot longer.

SouthSide2

here's 1990 block.

SouthSide2

The Opposite Side Dipstick Adapter: Bolt-On: For Chevy 305 and 350: K-Line KL9670

was found on eBay . It was meant to fit a 350 or 305. That's right... it is not a easy fit to the 400 block.
The 400 block has a thicker outside wall. This is still a good buy .
Down side is you have to make it fit. I had to grind/remove material to make it fit. And drill and tap for 1/4-28" screw's

sofakingdom

iTrader: (1)

On the 400 for my car, I simply used a stock-balance 400 damper; and had a new flywheel for my application (83 L69) "unbalanced" to the stock 400 balance spec.

Did I say "stock balance" enough times?

That way, the motor retains interchangeability with all other STOCK parts. No "special" ANYTHING required.

The balance spec for the 400 is something around 25 oz-in, directly opposite the rear (#7 & 8) crank throw. (directly in-line with the big funky shape on the crank flange) That works out to around 18 - 20 or so, 5/8" dia holes drilled around ½" deep, around the edge of that flywheel, clustered as near as practical to the point I just described.



That point being, conveniently enough, right directly opposite the dowel pin hole, since the added weight would need to be right directly in line w it... you can think of it as an addition to the funky shape itself, except instead of adding weight, you're taking away weight from the other side.

ANY shop can do this, by simply mounting a stock 400 flex plate and the flywheel to be balanced, back-to-back; then drilling the flywheel until the combo is neutral. In fact you could probably even do it at home with a lawn-mower-blade balancer type of deal, although I certainly don't recommend trying that.

I'll see if someday I can get un-lazy enough to find a flywheel like that and take a pic. I thought about it once, but then decided I would procrastinate, but then never even got around to that. That's sad... putting off procrastinating...

SouthSide2

Wow! rb89gta can shine a block. I looked at his album. Have to say that is slick!

rb89gta

Thanks SS, got a lot of time in it, too much to be honest! LOL, I could do the same, in 1/3 the time ... if I could get a shop set up for me and the way I work .

rb89gta

SJ, how's it going on your build ? I can't always get a signal to get online with my phone so I can't keep up with it all. I truly hope that you read my post objectively as I meant them to be. I don't tell anyone how they should build there's, I build mine for me, my family and friends . just didn't want you to take any ONE person 's ideas or philosophies as the one and only way to do things .
I really do look forward to hear how it works out for you .

SouthSide2

That was nice.

soul.justice

Wanted everyone to know I haven't died. Build has been put on hold for a month, my wife had a hysterectomy a few weeks ago so I haven't had much time to fool with the motor since I've mostly been taking care of her. Will update soon, got 5.7" rods ordered and a new scat external balance crank ordered and in the shop's hands I just haven't gotten down there to discuss decking with them.

rb85TA

Hope that all is well with your wife!
Family is ALWAYS! first in my book.
The engine build, sounds, solid & safe. ... I'm sure you'll be happy with it. ��

rb85TA

SoulJustice, did you ever get the engine built?

soul.justice

Not yet. Life happens sometimes. I've still got all the stuff but I'm currently saving up for the retrofit cam. In the process of looking at how I'm going to reroute the exhaust for the sfc's I found some cancer, so I've gotta get it fixed before proceeding anyway. Luckily it isn't much and everything else I've seen is surface rust, but this cancer is in the driver side wheel well, where the strut tower is. I'll post back once more progress is made.

Regal105

I have a 406 in my 86, it's my nice weather daily, 256 extreme energy camelhumps and a performer eps intake and 1406 carb cheap headers and a 3 inch exhaust with 342's out back stock converter and a 168 tooth flex. Small bodied starter is a must. My car drives great, replaced the 305 with the 406 and didn't look back. Built it to be faster than a 05 gt and it didn't disappoint. Good luck!