ryans01z28

im working on my buddies 86 iroc & im going to pull the heads off cuz i need to extract some exhaust bolts that r broke & was wondering since i have the heads of if i should have them shaved to bump compression? its pretty much all stock except for the LT's im putting on & coolant bypass im doing. how much added power would we b looking at & what head gaskets r best for this? thanks

ryans01z28

anyone??

redneckgames

dont even mess with it. You wont feel any noticeable power increase.

ryans01z28

yeah i was thinking that but thought i would ask since i dont know much about the 3rd gen's. i wasnt sure if they were very good heads to mod. thanks

mrbadlt1

I beg to differ. Shaving or milling the head can be beneficial to increase the compression ratio. Depending how much you are willing to cut the head. If i were you on a near stock car, i would take .020 off the cylinder head, and find a good head gasket with a thin compressed thinkness so you get a good seal. Running a thinner head gasket will also bring the cylinder head closer to the piston. Which will depend on stock head gasket comp. thickness and aftermarket gaskets.

ryans01z28

yeah true but these heads prob dont flow the best is what im thinking. i read the spiral heads really suck so guess these r better than thoes

Hylton

Don't bother. The more you shave, the more it messes with the intake seal (you lose the angle and will have to use liquid gasket). Yes, you will bump the compression but you will also have to run better gas.

The big restriction in the LB9 and L98 is the intake itself. It just doesn't flow as well as the stuff we have today. Pull of the throttle body and you will see how the airflow is restricted on the left hand side. Shaving the heads won't get you past that problem.

ryans01z28

ic ic i will have to look at the TB & look. ive heard theres something u can shve off behind it.. is that what they r talking about? some kind of bumps or numbs or something?

Hylton

Yes. You can shave it but you won't be able to get it all. Consider looking for a used Edelbrock Hi-flow intake. Some guys have also successfully used an intake set-up from an LT-1 but I have no idea what you need to complete that.

Hylton

BTW -

Here's an example of what kind of porting you would need to do to your stock intake in order to make over 300HP out of an L98:

http://www.thirdgen.org/techboard/al...p?albumid=4181

ryans01z28

if it were my car i would consider it but its not. im just tryin 2 find some extra power 4the guy with out spending a ton of money. we are doing some trading my work 4 snap-on tool box filled with tools lol & i dont want to fork out any money out of my pocket if i can help it.

Hylton

That's kind of tough with an L98. There is no "one thing" which will get you a noticeable difference in power. The best bang for the buck would be a set of used Vortec heads from a Yukon, Tahoe, etc, LT1 intake and a better cam.

ryans01z28

i just thought there would be alot of free mods like on my 01z28 that would all add up in hp

Hylton

Huge difference between the L98 and the LS1 my friend!

ryans01z28

well ya i was just saying i thought there may be a bunch of free mods LIKE the ls1/lt1