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Discussion Starter · #1 ·
I own a 1977 Pontiac 350 which obviously has low compression. My guess is 150 horsepower or so. I would like to reach ~350HP in a budget friendly way. I'd rather not re-bore to 383 yet. Any advice? :)
 

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the 3 Cs,cam,compression and carburation.For street driving pump gas friendly get your compression up too 9.5.Good 4 bbl carb and intake and cam to be selected with regard to type of trans,rear end gear and driving habits.Tom
 

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Just get a factory intake and a good pontiac QJ properly setup for your engine.You need to really look at the CR of your engine IMO.Start there and then everything else will fall in line.You need to go back to all the gearing and again what your driving will be.Too much cam in a strett car can make it not much fun to drive.Way too many questions this early in your build.Tom
 

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"I own a 1977 Pontiac 350 which obviously has low compression. My guess is 150 horsepower or so. I would like to reach ~350HP in a budget friendly way. I'd rather not re-bore to 383 yet. Any advice? :)

Well, 2 things you said, make this build difficult. Trying to make 350hp with a low compression stock stroke 350, at a price that is budget friendly, is all but impossible.

But, with a few good parts, you can make the "seat of the pants" feel, a lot more spunky.

The stock '77 350 is rated at 7.6 CR. So, the best way to increase power is to increase compression, and run a small "steep ramp" cam. such as the Lunati Voodoo 256.

To increase compression, and yet try to keep the cost down, you can use your 6x-4 heads. They need to be shaved down to less that 90cc. Most sites say the stock 6x-4's have about 93-94cc chambers, from the factory.

The next parts that will increase compression, is a pair of thin Cometic head gaskets. If the deck height is more than .010, then the .027 x 3.95 gaskets are probably best. If the deck height is .005, then the .036 x 3,95 gaskets are probably best. Many engine builders say that around .040 or slightly over is a good quench distance, but when it gets over .050, it helps promote detonation. :(

Here's the Voodoo 256 cam. It will increase cylinder pressure, and low end power.

http://www.lunatipower.com/Product.aspx?id=1774

For the shortblock, to keep cost down, you can go with Sealed Power 357P cast pistons, and resized cast rods, with ARP bolts. If your block will bore .060, that will give slightly more cubic inches & compression.The next step up, in rods, is the RPM brand 5140 forged rods, for $288. And the next step up in pistons, is probably the Auto-Tec brand, for just under $500 shipped. They are much lighter, can have the thinner metric rings, and more pin height, to reduce deck height, without cutting so much off the block deck.

http://www.summitracing.com/parts/slp-357p30

http://www.summitracing.com/parts/slp-357p60

Obviously, a really good competition valve job. using one piece stainless steel valves, is best. But. again, to keep the cost down, just a good street valve job, using your stock valves, will have to do. But, as mentioned, the 6x heads need to have some taken off the chamber side, to increase compression, and an equal amount should be taken off the intake side, to maintain intake manifold fit. :yes

As mentioned, an iron or Performer intake, with a GOOD Q-jet, is about as good as you can do, for your 350. If you decide on iron, I'd buy a '72 year model Q-jet intake. It will work with the 6x heads, but does not have the EGR valve provision. The going price for these seems to be about $100, or slightly more, shipped. And used Performer intakes seem to be available for around $150.

That's about all you can do, to the engine, on a really small budget. But, a stall converter and more rear gear will help improve low end grunt. :yes
 

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I should have clarified as far as cost/budget goes. I don't really have a budget but I just meant I'd like to save money where possible of course. What you said sounds great though, Don. I'd honestly rather just get new valves and heads than reuse the old ones if that's less than optimal. Also, if I'm to buy anything I'd really prefer that what I get be as compatible with a 383 as possible, just so I won't have to buy another new carb if I re-bore later on because the one I had bought doesn't have enough cfm or something.

What would you guys estimate the total cost of a 0.060 re-bore would be? Keeping in mind the cost to have someone do the boring if the block is structurally sound, the new pistons, etc.

There's an engine shop in town that I know would do the boring, but I'd just like a guesstimate on that or the new parts at least.
 

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"...if I'm to buy anything I'd really prefer that what I get be as compatible with a 383 as possible, just so I won't have to buy another new carb if I re-bore later on because the one I had bought doesn't have enough cfm or something..."

If you plan on going to 383, I'd consider doing it now. It's not a matter of a simple rebore. Building a 383 requires a 4" stroker crank, long rods, and special stroker pistons. Butler sells both a 4" and 4.25" stroker assembly.

http://www.jbp-pontiac.com/products/engines_assemblies/rotating_assemblies.html#407_413

A Q-jet will work equally as well with a 350, 383, 400, or 455. They provide as much fuel/air mixture as is needed by each engine. They were used on OHC six engines, 301's, 350.s, 400's, 428's, and 455's. Some are 750cfm, some are 800cfm. Either size will work on your 350 or 383. Even the 301 had an 800cfm. But most of the 455's had a 750. There are some 750's running down in the 10's and even 9's, in some Stock & Super Stock Pontiacs. So, they'll provide you with all the fuel you need, for your 350 or 383, or whatever. :yes

A '72 iron intake will also work equally as well with either early or late iron heads, or alum heads. If you go with an alum intake, I'd guess that a Peformer would work better on a 350, and possibly, an RPM or Chinese equivalent, might work slightly better, on a 383. If you drive in cold weather, an Edelbrock intake will be better, because they have the heat crossover, to heat up the intake and carb. :smile22:

I haven't had any machine work done lately. But I can't see a shop doing all the necessary(and correct) machine work, for less than $500-$600--probably more.

"... I'd honestly rather just get new valves and heads than reuse the old ones..."

OK, you can buy the older heads, to get more compression. But, that will cost a lot more. If you buy the popular big valve heads, like 12, 13, 16, 48, or 62, you'll have to pay probably $500-$800 for heads that still need valves, and a complete valve job, including new seats installed, to make 'em compatible with unleaded gas.(Some guys get by without the seats.)

If you go with some of the small chamber, small valve heads, like 17, 47, 11, you'll still need new valves, seats, etc--PLUS screw-in studs, which will probably add from $150 to $250 to the cost.

My personal preference would be a stroker, with 6x-4 heads, a Chinese 2-plane intake and a '76-'79 800cfm Q-jet(or 795cfm Edelbock Q-jet). With the added cubes, the Voodoo 262 might be a decent cam, if the CR is under 9:1.

Here's some numbers I'll plug into the Wallace CR calculator:

350 + 30, 4" stroke, 90cc heads, 3.8cc valve reliefs, .036 x 3.95 head gaskets, .005 deck height.

http://www.wallaceracing.com/cr_test2.php

Calculator says--8.71 CR

That should work good with the 262 Voodoo cam. I'd just guess this combo should be good for close to 350hp, or a little more.

https://www.lunatipower.com/Product.aspx?id=1775&gid=287

OR, if you wanna spend more, a higher compression 383, with a roller cam, will make over 400hp.

http://www.hotrod.com/how-to/engine/hppp-0712-small-bore-pontiac-engine-build/
 

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For sure a 400 would be a better choice.If you found a good block virtually everything from your 350 would work in it except pistons and you would need them anyway with any kind of overbore.Tom
 

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Just put a 100 shot plate kit on it.
 

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Discussion Starter · #12 ·
Hmm, looks like $500-750 for a decent 400 block, $500 maybe for the bore/clean, maybe $300 for good pistons. ~$1500 for a 400 then.

I'll probably just end up investing some money in my 350 to increase compression/hp in a pretty simple manner.

So what could I achieve with just a new carb and that voodoo camshaft? Would there be anything else along with that you guys would really recommend? New pistons?

Sorry if some of these questions are obvious to some of you, I'm still a beginner to engine performance and such.
 

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Hmm, looks like $500-750 for a decent 400 block, $500 maybe for the bore/clean, maybe $300 for good pistons. ~$1500 for a 400 then.

I'll probably just end up investing some money in my 350 to increase compression/hp in a pretty simple manner.

So what could I achieve with just a new carb and that voodoo camshaft? Would there be anything else along with that you guys would really recommend? New pistons?

Sorry if some of these questions are obvious to some of you, I'm still a beginner to engine performance and such.
This post contains several questions.

(Q-1) "... looks like $500-750 for a decent 400 block, $500 maybe for the bore/clean, maybe $300 for good pistons. ~$1500 for a 400 then..."

(A-1) Good #481988 blocks are still around for less than $500. Spotts sells 'em for $400. And they can build a shortblock for you.

http://www.spottsperformance.com/blocks.htm

Or you can buy a 400 block, and, as mentioned, use your 350 crank, and everything else that's bolted to it, except the pistons. OR, you can buy a stroker assembly for it and build a 428 or bigger cube engine, still using your 6x heads. Don't think you can have a DECENT 400 built for $1500. :no If you could, I'm sure lots of guys would be interested in one.

Most nowadays prefer at least the RPM 5140 forged rods, and Sealed Power/Speed Pro forged pistons. The best buy I've found in Pontiac engines is from Len Williams. The cheapest thing he has is a 400 shortblock with forged pistons and cast rods. But, he'll add forged rods, for a reasonable increase in price.

http://lenwilliamsautomachine.com/400_Short_Block.html

Here's his complete 400, with 6x heads, which is said to make around 385hp. $4000 + shipping

http://lenwilliamsautomachine.com/400_Long_Block.html

I like his 4.25" stroker shortblock,

http://lenwilliamsautomachine.com/455_Short_Block.html

For $4700 + shipping you can have a complete 455, with an Eagle crank & rods, and 6x heads. 400hp + and around 500ft lbs of torque. The reason I'm listing these engines is both to show what Len has available, and to show aprox what it will cost to have a good solid engine built, by someone with lots of Pontiac experience, who will build it right. And he furnishes all the parts. You don't need to find a block or heads. I and many others have learned 1st hand that a Chevy shop can really mess up a Pontiac engine build. :(

Sandoval also has a decent price on a 4.25" stroker shortblock.

http://www.sandovalperformance.com/#!product/prd12/2017678915/budget-series-shortblocks-starting-%40

(Q-2) "...So what could I achieve with just a new carb and that voodoo camshaft?..."

(A-1) IF the shortblock is in real good shape, a GOOD Q-jet & small Voodoo, will increase power some.

(Q-3) "... Would there be anything else along with that you guys would really recommend? New pistons?..."

)A-3) In order to benefit by the increase in cam, you MUST have a shortblock which has piston rings which are well sealed. So, I'd recommend a minimum of .030 overbore, with a minimum of Sealed Power 357P30 pistons and some good moly rings. Need to have the deck height cut to at least .010 or less. Also a minimum of a GOOD valve job. The thin Cometic brand head gaskets will increase compression, but cost around $200. And, I consider it VERY important to have all the machine and assembly work done by somebody who has experience building Pontiac engines. :yes
 

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"Used 455 blocks (bare w/ 2 bolt caps) - baked, shot peened,(completely cleaned) checked for cracks- $600.00"

I would rather spend the extra $200 to go with a 455 block over a 400 honestly. Aside from the crank, pistons, crank, and rods, along with a cam and carb upgrade, what wouldn't transfer from the 350? You mentioned I'd want new head gaskets and have the deck height cut. Also, you'd recommend I bore the 455 block to at least .03, correct? Is a .06 bore with a 455 reasonable?

$600 for block, $300 for forged rods, $300 for forged pistons, $150 for cam, $150 for carb, $200 max for head gaskets, $300 for cast crankshaft = ~$2300 for a 455 (using old parts). Maybe $2500 if I have to bore.

Does that sound about right?

Edit: Added crank to list
 

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Nope, don't think you can have a properly built 455 built for $2500, including all parts and labor. :no

If somebody knows of such a place, please post that info.

You left out quite a few necessary parts, like: oil pump & new shaft, timing set, rings, rod and main bearings, assorted gaskets, lifters(if those were not included in your $150 cam price), etc, etc.

The Len Williams 455 long block, and both the Len Williams & Sandoval 4.25" stroke short blocks, are the best values I've found. Only way I can see how to do it correctly, for less, is to have a real good friend, who can do it for you, with free labor.

"...Looks like heads are around $400 for a 455..."

6x heads are the best value there is, for a 455. Usable cores are about $200 a pair. Then SS valves are about $200 or more, plus guides, springs, machine work and labor. You can probably figure on around $700-$800 minimum, for a good set of 6x heads, if you get the cores for $200.

You can occasionally find 6X heads that are said to be ready to bolt on, a little cheaper. But these usually have stock 40 year old valves, and machine work of unknown quality.

"...Also, you'd recommend I bore the 455 block to at least .03, correct? Is a .06 bore with a 455 reasonable?.."

Some blocks can go .060--some can't. .030 is plenty, if all the cylinders will clean up @ .030.

"...$150 for carb,.."

What kind of carb are you going to buy for $150 ?

The news is not all bad tho. You won't need the $200 head gaskets. Lots of guys build 455's with the cheap 8518PT Fel-Pros, or the better 1016 FP's.

http://www.summitracing.com/parts/FEL-8518PT

http://www.summitracing.com/parts/FEL-1016
 

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Discussion Starter · #18 ·
Sorry, I should have said but I didn't include labour in the costs because I'm currently in a car class where we can build the engine as long as I supply the components. I'd just need the machine work outsourced, though I'm not sure how much machine work I'd need done. I may just end up buying a Len Williams assembly. As far as what I left out, will none of those items transfer from a 350?

Sent from my iPhone using Tapatalk
 

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Discussion Starter · #19 ·
If that doesn't work out I'll probably just stick to either a 400 with mostly 350 components or just make a 383.

Sent from my iPhone using Tapatalk
 

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"... As far as what I left out, will none of those items transfer from a 350?..."

Yeah, a lot of the parts that bolt on to a 350 will bolt on to a 400 or 455. pistons won't--crank will, in a 400--most everything else that bolts on to a 350, will bolt on to a 400 or 455. :yes

"...If that doesn't work out I'll probably just stick to either a 400 with mostly 350 components or just make a 383...."

A stock stroke 350, with cast pistons will be the cheapest, and make the least power.. Then a 400 will be next cheapest, and a 383 will be highest.
 
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