Slow87

My LG4 bottom end only has 35XXX miles on it so I'm not touching the bottom end. Everything I buy for my top end will be transferred to the 350 bottom end when it's finished. So don't bother telling me don't waist my money, because none of it will be wasted on machining a 305!

The "hate me" and carcrafts 305 build put out some pretty sweet numbers. I just want to break 300WHP. I wan't it to idle good and still be reliable. I'm looking for some suggestions on parts.

Exhaust is done- Hooker 2460 headers, with a full 3" exhaust all the way back.

Ignition- I have a MSD 8460 Dizzy,6al box, 8.5 msd wires,

Heads, I can only afford 700$ for the pair. Car craft pulled decent power out of their vortecs. I know that those will need machine work to fit a decent lift though. SUggestions?

Cam- I am completely clueless. both of those builds used a flat tappet cam so I can't follow their steps.Suggestion?

Intake- depends on the heads I go with but I was thinking the Victor JR

Carb- I would really like to stick with my Q-jet as it only has maybe 12,xxx miles since the rebuild. This saves me money and solves the toroque converter problem. I've read they're reliable and not as bad as everyone says. Suggestions?

Rear end- I'm in the process of picking up a 4th gen rear end. Will the 3.23 gears work for this amount of power or will I need the 3.73?

Stall size-3200

Edwardgp

Absolutely nothing wrong with keeping the Q-jet.

five7kid

iTrader: (14)

The q-jet won't fit on a Victor Jr. without an adapter. You will need to use a cowl hood to fit it all under if you go that route.

If you pick a cam that could use the Victor Jr. to its full potential, the factory q-jet will not be happy.

300 HP at the crank is do-able. 300 RWHP out of a 305 NA and factory q-jet is not a reasonable goal.

cal30_sniper

iTrader: (16)

Are you running a mechanical, or computer controlled Quadrajet? I love my mechanical quadrajets, I ran one on my '87 Formula, and I'm currently running one on my warmed over 454 Suburban and my 350 Oldsmobile Jet Boat. They are an extremely versatile carb, very adaptive to changing conditions, economical, and can make great power. I've never messed with the computer controlled quadrajets and have no intentions of ever doing so. Ditto on the computer controlled distributor on a carbureted car. If you want to put down the kind of numbers you're talking about out of a 305, you're going to want a carb you can jet and a distributor that you can adjust the advance curve on.

I did a lot of work on the 305 LG4 in my 87 Formy. I had reworked and slightly ported Corvette 113 Heads, a CompCams Xtreme Energy 258 camshaft, and a Weiand street warrior intake. Don't have a clue what kind of numbers I was putting down, but I'd say it was in or close to LT1 territory. If I had to do it again, and was stuck with a 305, here's the combo I'd be looking at:

-Vortech Heads (just run 26918 CompCams valvesprings. That should allow you to run a 480 lift cam with no problems, and no machining of the valve guides required)
-CompCams Xtreme Energy 264 Cam (I felt like I was leaving quite a bit on the table with the 258 cam. It just wasn't enough for what you want to do)(You may have to have the valve guides machined for this cam. You won't know until you check the actual valve to retainer clearance)
-Intake is where things get tough. If you want to keep the Quadrajet, you're pretty much limited to the Edelbrock Performer (or clones) or one of the GM Performance Intakes that come with the Vortec head crate motors. If you go square bore, the possibilities are endless. I feel like you'd be happy with the Performer Intake, but you might not quite make your 300hp goal. If you go with a squarebore, I would go with the weiand street warrior and not look back. It does clear the hood, you just have to use a dropped air cleaner.

You probably won't make over 300FWHP unless you have the heads machined down. The 64cc Vortecs are going to drop your compression ratio to around 8.3-8.5:1. However, if you machine them down, you're not going to like what they do to the compression ratio on a 350. You're probably better off building a compromise 305 based on parts that are going to work very well on a 350. There's a lot more difference between a 305 and a 350 than cubic inches belay, I learned that the hard way. The small bore on the 305 shrouds the valves really bad. Put the same parts on a 350, and you'll pick up a lot more than the 15% cubic inch increase would suggest, simply because you can unshroud those valves.

-cal30sniper

Slow87

You guys make some great points. I have changed my mind on everything! I'm ditching my 300WHP goal, because apparently its not realistic. I have to worry about the final goal which is the 350. I need parts that will work well with that. With that being said I want to chase 250WHP, and a setup that I can spray a 125 shot on once in a while.

New setup

L31 vortec heads
CompCams Xtreme Energy 264 Cam
super victor intake
I need suggestions on a carb
125 shot(since the compression will be so low)

I have to do a lot more research. Please tell me if I am just way off track here.

cal30_sniper

iTrader: (16)

A VERY mismatched combination. The Vortec heads and 264 cam are both very conducive to midrange power. You're looking a powerband of 1500-6000 rpm or so. Excellent midrange, great streetability, and something that will still perform great on your 305. The Victor Jr intake has a powerband of 3000-8500 rpm. It's going to be a dog down low. If you want to use the Victor Jr, you need to go way up in cam duration. You do that, and you're quickly going to have a combination that isn't going to work well at all on the 305.

With the Vortech heads and 264 cam, look at something like the Performer RPM or its Weiand equivalent, the Street Warrior.

You've got to decide whether you want to go mild or wild. If you want to go wild, forget about the 305 completely. I can't advise you on Nitrous at all, never messed with it. However, the iron Vortecs on a 305 keep compression pretty low, so that should be a viable option. As far as carbs, I'd say go with a Holley, but that's more of user preference. They're easy to tune and a great beginner carb.

-cal30sniper

Slow87

Okay then



If I went with the performer vortec intake with a spread bore(idle to 5500rpms) could I keep my CC quadrajet? OR do I need to just completely forget about the Q-jet and just go with a Holley 650 and a performer RPM air gap(1500-6500)?

cal30_sniper

iTrader: (16)

My vote would be with the Holley and the Performer RPM. I would be leary of the Air Gap, due to hood clearance considerations, but you might be able to get away with it. The Performer with a Quadrajet would be a perfect match for the XR264 cam. If you go with a Holley and a Performer RPM, you should probably look at stepping up to an XR270 or XR276 cam. I don't know if the 305 will be able to handle the XR276 though, you'd have to look at other members combinations. Either cam would put you right in the powerband of an RPM manifold on a 350. From builds that I've read, the XR270 should put you about 400FWHP with the 350. The XR276 should do even better, but you're going to start losing low end torque. You can expect the Performer Intake and 264 cam to make 375FWHP or so, but it will keep a bunch of torque in the lower RPMs as well.

I have never attempted to mess with tuning a CCC quadrajet, but from what I've heard, your options are extremely limited with adjustments. A regular quadrajet will do everything you want that motor to do and then some, just not the computer controlled one. Keep in mind that a mechanical Quadrajet or Holley will also require the use of a mechanical/vacuum advance distributor and an independent torque converter lock-up device.

The way I see it, you're really looking at two options here:

Option #1
Performer Intake
XR-264 Cam
Mechanical Quadrajet or Holley

Option #2
Performer RPM Intake
XR-270 or XR-276 cam
Holley

Option #1 will work great on your 305, and produce respectable power out of a 350. Option #2 will be overkill for the 305, but it will make a beast when you transfer over to a 350.

Slow87

I have a msd 8460 Distributor. It is Vacuum advanced. If you google it, you won't find anything on it. They replaced it with a 8360 model, but they're the exact same.

The torque converter was why I was so eager to keep my Q-jet.

Looks like I'm going with option #1. Thanks a lot sniper, you been a big help!

five7kid

iTrader: (14)

The Air Gap doesn't put the carb any higher than the non-air gap manifold of the same type (Performer vs. Performer Air Gap, or Performer RPM vs. Performer RPM Air Gap) does.

makaveli09

i had a performer air-gap(2601) with a Q-jet.with a XE 268 with long tubes duals
on my L69 years ago. and it ran great.
if i where you i would try to find a set of 113 vette heads. clean them up a bit and you would have a good street motor.

johnw999

Sniper - did you have someone rebuild your 305 with the performance parts? I live in DFW TX, and rebuilding my l69 305 is one option that I'm considering. If I do rebuild the 305, I would like to:
-use my existing quadrajet and distributer
-use heads and intake that can transfer over to a 350 if I ever go that route later
-increase power but maintain good idle and drivablility
-keep stock hood

What would you suggest? Maybe L98 heads and performer rpm intake.

IROC-BOB86

I'm looking to do the same thing to my 86 iroc, dont know how it will work at low rpm but looking in to it. check this link out.http://www.popularhotrodding.com/eng...s/viewall.html

cal30_sniper

iTrader: (16)

I had two things to say, and the article IROC BOB posted said the first one, but I'll recap my experiences anyways...

I did all the work myself. The engine was a factory 80k motor when I took it apart, so I didn't touch the rotating assembly. All I did was change the cam, seals, gaskets, oil pump, timing chain, and valvetrain, as well as add the Aluminum L98 heads.

If you absolutely had to do a 305, I probably wouldn't start with an L69. Look for one of the later, high compression roller cam blocks. The flat tappet cam is going to be a hindrance. You can get around it, but you're going to lose a lot of streetability out of that small motor if you start pushing a flat-tappet cam that's big enough to make any power. The roller can move the same amount of air in a shorter duration, pushing the powerband back down where the 305 likes to live.

L98 heads on a 305 is wasted effort, even the aluminum ones. Any added flow is more than cancelled out by the drop in compression. If you're going to do it, go with Vortecs. If you absolutely must have aluminum, look at something like Trick Flow's 305 aluminum head. Then again, if you've got that kind of money to blow, just get a 350, you'll be much happier. I'll explain why below...

That article is pretty good, but there's a few devils in the details that they're not really talking about...

1. They milled the heads to 60cc. They claim they are building an engine that: . That's going to be about a 10.5:1 compression ratio with iron heads if you ever try to swap the now milled Vortecs onto even a factory 350 short block. Try it with a rebuild and flat-top pistons and you're going to have all sorts of major issues on your hands. They milled the heads to make more power, but in the process almost ruin their ability to be ever run on a 350. Not a smart idea, purely there to inflate the numbers on their test.

2. A lot of talk goes into the bore to stroke ratio on the 305, but the ratio has nothing to do with why the 305 won't make power. The small bore on the 305 is not terribly small in comparison to it's stroke, but it is very small in comparison to the valve size. A 1.94" intake valve opening into a 3.73" bore is going to be nastily shrouded. THAT is what keeps 305s from ever making the power of their only slightly larger 350 brethren. They share the same stroke, so the 350 has a much larger bore to valve size ratio, and thus much less shrouding.

3. They keep talking about bigger cams, and running the little 305 over 6000 rpms. You don't want to do that. The XE268 is already a very large cam for the 305. You are going to give up a lot of torque down low, and you're going to be choked by bore size up top. Not good.

4. I'm telling you from personal experience, if you want to warm up a 305 on the cheap, go for it. But don't expect magical numbers, and if you optimize the parts for the 305, don't expect them to work perfectly (or even at all in some cases) on a 350. You've got to make up your mind early on if the 305 is a stopgap, or the end state. I dumped a bunch of money into speed parts for a 305, only to realize that when I finally got a 350, I wanted everything (heads, cam, etc) to be bigger. The 350 is simply a much better performance engine, end of story. The 305 is great for economy, and can be made into a decent warmed over daily driver, but it will always pale in comparison to what a 350 can do with the same parts. Personally, I won't ever waste money on trying to make a 305 go fast again. 350 short blocks are just too cheap.

-cal30sniper

afremont

Yeah, I'd just try to find some 58cc heads instead of ruining a good set of 64cc heads by shaving them down to the valve faces. They'll never seal right to the intake without machining it anyway. Cams are cheap, trying to pick something small enough for a 305 yet big enough for a 350 is pointless AND futile.

I have a summit 1102 in a 305 with flat-tops and 58cc heads, it lopes nicely. I doubt that it would be even noticeable in a 350. I'm using 305 heads so they have sensibly sized runners and valves for the street. I don't run stall convertors so I don't run big cams, carbs, intakes or valves on my toys.

cal30_sniper

iTrader: (16)

A 64cc iron head (or 58cc aluminum head) will run just fine on a 305. You pick up a few more horses by milling down, but it's just not worth it, because you're ruining them for a 350 later on.

I liked the Comp XR258 for DD duty in my 305. Think of it as a modernized L98 cam with a bit more heat. I think the XR264 would have given it much more mid-range and top-end punch though.

For a low-budget 305 build (that could easily be switched into a powerful 350 later on), I'd go with 64cc iron Vortec heads, and a used LT1 cam. You can pick up the heads for a couple of hundred bucks, and the cam for $25 if you watch what you're doing, and it will play just fine with the Vortec valvesprings. I'd also strongly consider the GMPP Ramjet 350/HT383 cam. That would be sweet in a Vortec head 305, and you can pick them up pretty cheap on occasion. It's another cam that drops right into the Vortec valve lift range, even with 1.6:1 rockers.

As long as you don't expect too much out of it, you'll be pleased. Once you're done fooling with the 305, you're a cam/valvespring swap away from putting down great numbers in a 350.

Run a higher stall converter and tighter gears behind that 305. It will work wonders for the seat of the pants feel.

-cal30sniper

bestracing

A 64cc head works fine on a 350 motor, you just have to have the right pistons (dished) for a good compression ratio and as long as it's a 2.02/1.60 valve head. Like you said before the larger valves don't work well with a 305 and IMHO the smaller 1.94" valves is not optimal on a 350 motor.

cal30_sniper

iTrader: (16)

The factory 350s in our cars came with 64cc heads, as did many other 350s (including all the Vortecs). Reread the post, the problem is not with a 64cc head on a 350, the problem is milling a 64cc head down to 60cc to bring up the compression on a 305, and then trying to put it on a 350 later on. That's when you're going to have major compression issues.

Many, many powerful 350s have been built on 1.94" valves. 1.94" valves work great on 305s too. You might have serious clearance problems running 2.02" valves on a 305, depending on the head design. Either way, the 305 is going to shroud any size valve much worse than a 350 will.

johnw999

Thanks - that answers my question. The 350 is probably in my future. In another thread, I've shown interest in the 300hp 350 crate engine shown here:
http://paceperformance.com/i-6237688...no-intake.html

But, others have encourage me to get the 350 vortec shown here:
http://paceperformance.com/i-6484922...-4-ton-up.html

I want to keep my original carb and distributor. I'm ok with switching the tank helper pump to a stronger electric pump. But, I am concerned that my distributor won't work on the vortec. I also wonder if the oil pan is too big. Do you know if anyone has gone that route with a write up on how to do it? Thanks

cal30_sniper

iTrader: (16)

That vortec motor is exactly what you want. The 300hp 350 is a flat tappet cam motor. It's easily worth the extra $200 to get the roller cam and Vortec heads.

It's nearly a drop in operation. You will need a Vortec pattern intake manifold for your carburetor, and you will need an electric fuel pump (you can't use a mechanical fuel pump, the newer block does not have provisions for it). The oil pan is for a truck, but any one piece real main seal oil pan from a 3rd Gen will bolt right up. The truck oil pan might even work, I don't know on that. Depending on what year your car is, you may already have a one piece RMS, so then you could just swap over the oil pan. Ditto on the flexplate/flywheel. You will need one for a one piece rear main seal. The only other thing I could think you would need is a passenger side dipstick tube if you don't have one already.

Below the heads, the Vortec is nothing more than a roller cam, one piece RMS, small block chevy. Identical block and rotating assembly to what came in the '87-up L98 cars. I would strongly advise you go with the Vortec motor. It is only a cam swap away from 400hp.

-cal30sniper

johnw999

Alrighty. I'll prepare my car for the engine swap (pull the 305). Then I'll wait for a black friday deal in November. Deal or no deal, the order goes in by December 1.

b1k1w1

You may know this but just in case the vortec also came as a 305. Also you will have to do work to put a cam over 480 lift with vortec heads. But the vortec 350 is the best deal just ask before you buy and end up with two 305s. If you where to get the vortec heads and intake and have it cut to 58cc for the 305 you could always sale it.