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350 budget build for a disco era Skylark * Nova? Omega ! Ventura %
Hello everyone!!
I might as well start a thread for my olds 350 rebuild.
The plan=
Fun and reliable daily driver with some *****!!!
The car= not and olds but olds power!!
I found a 1974 olds 350 on craigslist for 200.00 to transplant into the skylark all it needed was a tune some gaskets and disco gold!! It runs great, but I want more so I found a 1972 350 with 7a heads, never been opened up, still had original nylon timing gear.
The engine 1972 Olds 350=
9-1 or 9.5-1 compression goal
300hp goal
The shop= Baker machine shop Tucson Arizona
The heads are done, well maybe = 390.00 Most likely upgrading springs
with cam choice later Be doing new springs with cam.
Leaning towards a lunati Street master part # 10420312
The short block is at the shop for tear down and inspection to see how bad it
needs to be cut up.
The plan is doing a 650 dollar rebuild kit from summit racing, forged flat tops are included
with ring bearings, oil pump, gaskets.
kicking around the idea of a 3.5 stoker, but might be too much$$
Last edited by AZ520; October 21st, 2017 at 07:19 AM.
That is a decent cam choice but the flat top pistons will put your compression too high with the 7a heads. They would work with the 1974 #8 heads. You need the LF2321 5.8cc dish pistons or splurge for Mahle's new piston that Cutlassefi convinced them to make. More money but 10+ more horsepower from the modern ring pack and put your compression where it needs to be. The 3.5" stroker allows cheaper sbc parts to be used. What work was done to your heads?
Last edited by olds 307 and 403; October 21st, 2017 at 07:40 AM.
The heads were just a standard rebuild, seats and guides cut or replaced as needed, springs checked with new seals. I will have them install new springs with a cam. I was originally going to toss them on the current engine with a cam, but figured I would just do a full build on the other engine. If the block is buildable they will cc the heads and will know more when the time comes.
It sounds like I might get away with standard cast pistons from rock auto rebuild kit you think?? That will save a few hundred!
No, unless your heads cc at 60 or less, which they won't, you need small dish pistons. The 24cc regular cast dish pistons are also shorter than the Speedpro which are also slightly shorter than the Mahle and other modern forged pistons for the Olds 350. Lower compression height lowers compression and ruins quench.
I have read that stock 68-72 heads are 64cc new, but also read that 71-72 are 68cc-69cc so I guess I will know more once they cc them and we can see which pistons to go with. I told them about using chevy rods and pistons and they were curios, so maybe they will do some research or know someone who knows.
What did the heads CC at? My #6 heads were 62-64cc but were cut. Mine had the bowls open with a cutter and a 2.05" intake valve. What pistons did you go with? You will need a fairly big cam for 300 hp with stock heads. Get the Performer RPM intake, just better with no bottom end loss. Good part is 350 ft/lbs of torque is easy peasy.
I am betting the heads are around 68cc. They only needed surfacing. They should know before pistons are ordered. The gaskets will be fel-pro standards .040.
I already have the performer 2711 intake.
I also have the comp cams roller tip rocker kit, debating on sending it back, because I have read some bad things about it.
I am hoping for 300hp with a very broad torque curve.
If you're shooting for a stump puller then don't use that cam. Use a single pattern on a tighter lobe sep.
HOWEVER- by focusing on low end you'll be making it harder to make your hp goal. Just sayin.
Thanks for the insights, I already received that have that cam. It should be ok ?? Its listed as a broad torque cam. This is my first go at this so I am just going by what I have been reading and the specs of the parts. The engine shop doesn't do many olds engine either to make matters worse.
Most who have used that cam like it, just make sure they use the right pistons for 9+ to 1 compression. I would up your torque converter stall to 2000 minimum since it is super easy with the motor out.
I have read that stock 68-72 heads are 64cc new, but also read that 71-72 are 68cc-69cc so I guess I will know more once they cc them and we can see which pistons to go with. I told them about using chevy rods and pistons and they were curios, so maybe they will do some research or know someone who knows.
FYI as cast 1967 #4 heads are 64 cc.
All other SBO 1968-1972 heads are 68-69cc as cast.
CC your heads to determine if they are stock or milled before you start choosing cams, pistons and head gaskets.
That's the same cam in my engine but under the old UltraDyne name before Harold Brookshire sold his designs to Lunati. While it's a great cam, I wouldn't label it as a stump puller. And I agree you will need a higher RPM stall converter. I have a 2500 and it seems appropriate for the power band.
Originally Posted by AZ520
I already have the performer 2711 intake.
Sell it and put the money towards a Performer RPM. I started with a Performer 350 and noticed a significant improvement with the RPM.
Originally Posted by AZ520
I also have the comp cams roller tip rocker kit, debating on sending it back, because I have read some bad things about it.
The only bad I have read is the push rods are the wrong length and the stamped locks come loose. You need to measure what length push rods YOUR engine needs and order the correct size, and also use polylocks instead of the supplied lock nuts. That is what I did over 10 years ago and no complaints yet.
Too bad I ordered all the parts, the cam is listed as a idle to 5500 so I assumed it would work good with the performer and stock head combo, thanks for all the help, I can still sent the rockers back and just get the stock kit they sell. The compression will be between 9 to 10. Why do you need custom cut push rod or adjustable it the heads are not milled?
The cam will work OK with that intake, it would just work better with the RPM intake.
Several reasons for measuring push rod length:
You are installing the heads with .040" thick composition head gaskets and not the factory .017" steel shim head gaskets.
There are manufacturing tolerances in everything, such as lifter length, camshaft base circle, block deck height, head surface, valve stem height (which can change due to valve job, new valve installation, etc.) so you need to measure the length needed for a particular engine. The lifter preload can compensate for a bit of variation, but if things get outside that range then a different length push rod is needed.
And most of all, everything I have read says the ones in the kit are the wrong length to start with.
Last edited by Fun71; November 13th, 2017 at 04:39 PM.
Get true roller rockers if you are exchanging them. The Comp roller rips are well made but not true roller rockers. There is supposedly as much as 30 hp to gain with true roller rocker arms. Scorpion and Harland Sharp are two good brands.
I have been thinking about just getting some roller rockers, whats another 300.00 at this point. Summit has some scorps for 3/8 studs for 290.00. All i would need are 5/16 to 3/8 studs.
Would I need guide plates? The spring tension will be around 350lbs. according to the cam card.
Looks like the heads cc at 62, so with the -5.8 speed-pro and fel-pro head gaskets that put the compression ratio at 9.8 : 1. Thats a little higher than I wanted, but will work. They are going to balance the rotating assy. and recommended arp rod bolts so I said ok!
Looks like the heads cc at 62, so with the -5.8 speed-pro and fel-pro head gaskets that put the compression ratio at 9.8 : 1. Thats a little higher than I wanted, but will work. They are going to balance the rotating assy. and recommended arp rod bolts so I said ok!
Stock those heads were 68-69 cc. You may need to mill your intake. Check with an expert before you bolt it on.
This engine has never been apart, he said he had a book showing 60- 80 cc variations from the factory, I told him I though they only came around 68cc. He was pretty sure they were 62cc from the factory?
Then the heads did not "cc at 62" - in order to cc heads, they must be removed from the engine and the volume of combustion chambers measured very precisely.
Originally Posted by AZ520
he said he had a book showing 60- 80 cc variations from the factory, I told him I though they only came around 68cc. He was pretty sure they were 62cc from the factory?
So he doesn't know much about Olds heads, and you are basing your engine build around his "guess" at the head volume.
Just pull the heads and measure them. It's the only way you can know.
Originally Posted by oldsmobiledave
Check with an expert before you bolt it on.
And I think we have ascertained that the current builder is not that person.
Last edited by Fun71; November 21st, 2017 at 09:22 PM.
The engine is at his shop being rebuilt, they have the heads off the engine! and they rebuilt the heads and he said that is not correct information. They cc'd the heads at 62 and the book he has states that from the factory they could have that size. All the info on the net is all over the place about this. I found this engine on craigslist and it appears to have never been rebuilt , it had a nylon timing gear and std. pistons and bearing. I talked with them over the phone so I need to see what book he is getting the info from when I go to the shop. This is an old school 2 generation family shop and they seem to know there stuff, just don't see many oldsmobile engines to be considered olds experts.
The engine is at his shop being rebuilt, they have the heads off the engine! and they rebuilt the heads and he said that is not correct information. They cc'd the heads at 62 and the book he has states that from the factory they could have that size. All the info on the net is all over the place about this. I found this engine on craigslist and it appears to have never been rebuilt , it had a nylon timing gear and std. pistons and bearing. I talked with them over the phone so I need to see what book he is getting the info from when I go to the shop. This is an old school 2 generation family shop and they seem to know there stuff, just don't see many oldsmobile engines to be considered olds experts.
Just a word of advice. It is highly unlikely to impossible that as cast #7a heads will cc at 62cc. Either the heads have been milled or they were not correctly cc'd. This "book" is wrong. Only #4 cylinder heads were 64cc as cast. This has been discussed many times on this forum and elsewhere.
Those heads have been cut. One of my heads was cut twice for that CC. Yes they do vary but not that much. That is very high compression, your cam may actually be on the small side. Premium gas and conservative timing with an adjustable or limited advance will probably be needed. A good polish on the combustion chambers might help detonation, increases CC and smoothes out rough spots in the chambers.
Bill is good, a national record holder with Olds power. Remember those heads are now nearly 50 years old. If they were rebuilt, almost guaranteed they were milled some. They may have been rebuilt in the past as well. A Builder said a .006" cut is 1cc removed from an Olds combustion chamber FYI.
Here is an example. The #8 heads are supposed to measure 79cc from the factory. My untouched sets measured 77 to 78cc. My 4A heads measured 86cc vs the 84cc they were supposed to be. Many on this site have measured the 330 heads which are around that 64cc measurement and the later 350 heads are about 5cc more. If they are measured properly, then they are 62cc. I would only use the early Turkey tray intake gaskets, even that is tight on my 350, now way the composite intake gaskets will fit.
Here is an example. The #8 heads are supposed to measure 79cc from the factory. My untouched sets measured 77 to 78cc. My 4A heads measured 86cc vs the 84cc they were supposed to be. Many on this site have measured the 330 heads which are around that 64cc measurement and the later 350 heads are about 5cc more. If they are measured properly, then they are 62cc. I would only use the early Turkey tray intake gaskets, even that is tight on my 350, now way the composite intake gaskets will fit.
Just to be clear ONLY the #4 heads are 64 cc. The 1, 2, 3 heads are 68-69cc as were the later 5,6,7,7a heads. Again this is as cast. Always cc your heads before picking head gaskets and pistons or your compression ratio will be only a guess....the actually compression may result in miss matched parts.
Really, have you measured the 1,2 and 3? Not saying it isn't true but accurate info us what makes this site what it is. I know one guy measured his #3 heads at 61cc. That was with a clean up mill. Like any 50 year old heads they could have been milled multiple times. Let's face it how many cars are original owner and TRULY know if the heads measured have never been milled. My question is why just the #4 heads? It make sense due to the smaller bore that the 330 heads would have smaller chambers.
I am going to check out this book he is looking at, I told him about all this and he assured me that his info is correct, that the camber sizes are varied on these Oldsmobile engines.
I am going to check out this book he is looking at, I told him about all this and he assured me that his info is correct, that the camber sizes are varied on these Oldsmobile engines.
Please take a photo of your man's book and post in this thread. We'd all love to see this "bible".
Take Mark's (cutlassefi) post as gospel. He just cc'd a set of 7a's at 68 cc after the heads were prepped.
Again good luck with your project. Everyone here is posting with good intentions & trying to help you.
I do appreciate any help and info, that why most people come onto forums to seek help and information. This has been my go to for most of the olds information I am after. I have an open mind about stuff especially when it comes to information found on the net. I am the type of person who needs to see things for myself, once it comes time to fit the intake I will be 100% certain that the heads have been milled down or not. I will have a look at this book and take pictures of coarse because the head volume of the olds small block has been shrouded in mystery for long enough
Stopped of at the machine shop today, looks like his bible is just a sealed power piston catalog, listing compression ratio with head cc. I will let everyone know how the intake lines up.
October 21st, 2017, 07:15 AM
