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Heads

J

Jonathanlackey

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I'm looking at changing the heads on my jimmy while keeping the bottom end the same. Was wondering if anyone had any recommendations and or any heads to stay away from. Mine has the gm 882 heads on it. Also if anyone knows what heads come in the 1974 Gmc Jimmy 350 sbc with those heads that would also be helpful. I am trying to keep the compression under or around 9.5, while getting a 65cc to 70cc combustion volume and 155cc to 175cc intake port volume, if anyone knows the casting numbers to a set of heads that fit that description.
 
882's are junk.

New heads can be cost effective. If you were to find vintage 74 heads that hadn't been machined to tiny combustion chamber volume over the years, and have them hard seated( for unleaded) and new guides, valves, springs, and labor to all that. you'll be close to ready to go aftermarket price if not more.
The modern oem chevy heads that have hard seats will save you some money but are all light casting heads,not deal breaker.
If you went with Vortec heads would add manifold to expense.
 
Wes Harden said:
882's are junk.

New heads can be cost effective. If you were to find vintage 74 heads that hadn't been machined to tiny combustion chamber volume over the years, and have them hard seated( for unleaded) and new guides, valves, springs, and labor to all that. you'll be close to ready to go aftermarket price if not more.
The modern oem chevy heads that have hard seats will save you some money but are all light casting heads,not deal breaker.
If you went with Vortec heads would add manifold to expense.
Click to expand...
I have a gm preformance vortec intake manafold and a edelbroke regular intake manafold from one of my dads builds im more worried about if i have flat pistons or not
 
Hogback Fabrication said:
The 882's are bad emission era heads for sure, but unfortunately almost everything out there for a Gen I small block is like that.

The '96-99 Vortecs are generally considered the best factory Gen I/II small block head.

https://www.summitracing.com/parts/...pgJ-T7FH544tNhT_uAKeNzZHNyKqmNOxoCA4YQAvD_BwE

That does require different valve covers and a different intake manifold.
Click to expand...
not worried about the vaulve covers i have a gm preformance vortec intake manafold im more worried about whether or not i have flat pistons or not
 
Um 1974 chances are slim to none you have flat top pistons, if the engine is oem. In 74 993 were used but I would stay away from these 993 have the double heat riser passage and are prone to cracking. 3986388 are 350 used on trucks 69 to 79 with accessory bolts hole. Small valves 1.72 i and 1.50 e, 76cc combustion, will be smaller when heads are machined. Could be much smaller if heads have been machined before. These are nothing special heads. Will be good sound work truck heads thou.
 
I understand the idea of keeping them budget. Just know that taking an old set of cylinder heads, a lot of them will need rebuilt and I
Jonathanlackey said:
Trying to stay as budget friendly as possible, so kind of hard
Click to expand...
I understand the idea of keeping them budget. Just know that taking an old set of cylinder heads, a lot of them will need rebuilt and that’s gonna be north of $500. You might want to budget that into your purchase price if you’re buying used.
 
Bent77 said:
I understand the idea of keeping them budget. Just know that taking an old set of cylinder heads, a lot of them will need rebuilt and I

I understand the idea of keeping them budget. Just know that taking an old set of cylinder heads, a lot of them will need rebuilt and that’s gonna be north of $500. You might want to budget that into your purchase price if you’re buying used.
Click to expand...


Been hitting the hooch there @Bent77
 
I took 882’s off a 350, and put the vortec kit on from Scoggin Dickey chevrolet. Kit included everything! Only thing they didnt cover was running a bypass hose from the intake to the water pump. I tore it down thinking I had a bad head gasket, then got asking questions about the conversion and found that out.
The performances increase was so great, it was like a new engine!
 
Wes Harden said:
Um 1974 chances are slim to none you have flat top pistons, if the engine is oem. In 74 993 were used but I would stay away from these 993 have the double heat riser passage and are prone to cracking. 3986388 are 350 used on trucks 69 to 79 with accessory bolts hole. Small valves 1.72 i and 1.50 e, 76cc combustion, will be smaller when heads are machined. Could be much smaller if heads have been machined before. These are nothing special heads. Will be good sound work truck heads thou.
Click to expand...
is 3986388 the head casting numbers and i didnt mean to say flat top i meant flat tappet
 
Wes Harden said:
Um 1974 chances are slim to none you have flat top pistons, if the engine is oem. In 74 993 were used but I would stay away from these 993 have the double heat riser passage and are prone to cracking. 3986388 are 350 used on trucks 69 to 79 with accessory bolts hole. Small valves 1.72 i and 1.50 e, 76cc combustion, will be smaller when heads are machined. Could be much smaller if heads have been machined before. These are nothing special heads. Will be good sound work truck heads thou.
Click to expand...
my dad has a set of 062 vortec heads that I can use but we were warned about gen 2 vorted heads and intake making to much compression on a gen 1 block
 
So I am unsure of this gen 2 vortec head. I know many people have put the 8 intake bolt heads on gen 1 sbc.( 2 piece rear main) and not had issues.

Those heads need to be checked for cracks, self aligning rockers, and a total lift of less than 500 or 550 depending on who you ask. Would go to high on spring pressure with stock press in studs either.

64cc chambers if unmolested. Many gen 1 sbc heads are 64cc
 
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