visionary

Looks like I have a blown head gasket on my stock 81 4 speed. Since I have to change it what are the best things to do to improve the performance without getting far away from stock. I plan to get hooker header sidepipes, perhaps a better camshaft and lifters. Anyone have experience with a newer fuel injection instead of the carb. Let me know what you have done that has worked well.

Thanks
Mike F.

calwldlife

a good chance to document the process and
how to

you are dealing with 8.2 compression.
an up point of cr is a must.

so, can you do a complete overhaul?

anyway, good luck

visionary

I could, but really don't want to...

calwldlife

don't blame you

then heads with small CC size and hope the pistons don't object,
fuel injection would be sweet

Fast81

Aftermarket iron heads with 62-64cc chambers to help that 8.2 (really more like 7.8-7.9) CR and masquerade as stockers

68post

https://www.trickflow.com/parts/tfs-30310001

or

https://www.trickflow.com/parts/tfs-30210006

visionary

I looked at these heads and they are nice. I also noticed the combustion chamber in these are small (60cc and 56cc respectively). Can the stock heads be machined in any way (decking)to get close to the specs these heads have? I'm trying to keep the matching numbers stuff but on this one it's a hard choice because there isn't a whole lot of hp to begin with. Any guess how much hp can be gained with headers, cam, lifters and possibly heads? Thanks!

calwldlife

heads are not really numbers stamped like a block.
2 things heads do.
squeeze the gas.air to a pressure that
gives better explosion.
gets air.fuel in and out of engine.

flow and compression.
done with valve size and chamber size.

then a cam is used to pick when the flow and compression
make power.

Big2Bird

I'm wondering how far you can go, and keep the ECM and pass smog.

Those heads look impressive for CARB approved.

cv67

Put the stock ones aside, spring for the aftermarkets with the small chamber. If you spend $ on anything do that,EFI a waste of money unless you just have to have it. Qjets are great carbs.

derekderek

Side pipes. Emissions in your state? Also, even if emissions exempt, side pipes scream "We don' need no steenking catalytic converters!" Some cops could decide emissions exempt and removing emissions equipment are 2 different things...

derekderek

As far as stock 72 cc heads... No. You can't make them make any kind of power without being a porting magician. And could never shave enough to get decent compression. Stock 96-2000 vortec heads are a good inexpensive upgrade. Make sure they are vortec and not TBI era heads. You will need a correct intake to match. Aluminum heads would be the best way to go, but more dinero...

derekderek

Blown head gasket. First you pull the heads and make sure your block deck is good before you buy anything.

visionary

I looked these up...about $600 a pair new and complete. They were labeled "marine heads. Is that right?

Fast81

Most shops wont touch your stock heads as they were "lightened" by GM of so much material they almost all crack..........and thats without any porting or planing ! You cant spend enough $$$$$ to make your stockers even close to the avg aftermarket head. Tech has moved ahead since the 70's

68post

^^Exactly what everyone's saying is the gospel, the stock heads are doorstops. Everything done right with good aftermarket ; heads, cam, good intake, and an excellent exhaust, will be close enough that if it doesn't gain a full 100 HP - it will sure feel like it...and then some !

And then there's gears...

Big2Bird

I wonder what cam would go with these, CARB approved.

https://www.trickflow.com/parts/tfs-30310001

CheezMoe

Assuming you only lost one side, I would do a leak test on all the cylinders on the good side. I've seen many attempts to place new sealed small chamber heads on a worn bottom end and quickly end up with blow-by in a cylinder or two. Proceed with caution!

68post

Here are two: http://www.jegs.com/i/Crane-Cams/271/100042/10002/-1

http://www.compcams.com/Company/CC/c...x?csid=73&sb=2

..and the comp 260HE is also "carb legal".

Black4speed

Since you have an 81 don't forget about the computer.