Camarokid327

iTrader: (4)

I pick up a set of 243 heads fresh from a machine shop where they received a 5 angle valve job, .005 removed for cleaning, and had the chambers smoothed.

My question is what gasket thickness would you guys recommend running to bump compression (maybe ~ 11.1) and have optimal quench all while having enough PTV clearance?

Cam: 228/228 .588/.588 112

Apologize for my ignorance, first time build and trying to wrap my head around everything I'm read in my searches.

Thanks so much in advance guys.

Tuskyz28

What pistons is in your motor?

Camarokid327

iTrader: (4)

sorry, stock bottom end.

Know It All

A Cometic .040" thick x 3.910" bore would get you there. Should put you at about 11.1:1.

.boB

iTrader: (1)

Stock deck height is about +.006-.007. Meaning that the pistons sticks out of the block about that much. A .040 head gasket gives you a quench distance of about .033-.034. That's cutting it a bit close for a stock bottom end. If you're going to keep the rpm's well below 6,000, you might be able to get away with it. Otherwise, you ruin the risk of the pistons hitting the heads.

Perfect quench is about .040.

96capricemgr

iTrader: (1)

Those folks in the real world understand that .033(worse case on .bob's assumptions) is just fine especially when considering the aluminum block will grow and raise the number.

.032-.035 is common in iron SBC engines turned 7000rpm.

Camarokid327

iTrader: (4)

So if I run a .040 gaskets I should be good?? ( 98-02 LS1 Cometic MLS 3.910" Head Gasket .040) The car is an auto so I don't have to worry about accidentally spinning it too high.

.boB

iTrader: (1)

Lots of factors go in to the equation: block growth, rod stretch, piston rock, etc. If you have a close tolerance race engine with new forged parts, and you can keep the temperature well controlled, you can run a pretty tight quench. Lots of race engines run 0.030-.035 quench with good results. Lots of "low" rpm truck engines also run clearances that tight with good results.

How much will a used 14 year old rotating assembly stretch at 6,000 rpm? How much will a 14 year old block grow? How much piston rock will you get at 20* or 210*? I don't know what the answers are to those questions. Are you looking for every last bit of power in a race car? or Longevity in a street car? Can you afford a catastrophic failure if you choose wrong?

Do your own research, and take your chances.

96capricemgr

iTrader: (1)

For a 2618 piston setup with the additional rock caused by the larger piston to wall clearance I might aim a little larger but with stock or 4032 pistons that fit tight and in older iron blocks that grow less than aluminum. .032-.035 has proven time and time again to be just fine. Yes the LS1 is a different engine but the aluminum block grows more just providing more safety.

It would be worth measuring stock just to be sure where you are now.

kinglt-1

iTrader: (26)

I will be running 61cc 243's on a stock bottom end LS1 with a 227/231 .580 .584 112 cam @ 1.85 and a cometic .045 gasket. Not sure if that helps or not.

voda1

iTrader: (4)

Anyone know where to get those?

squalor

iTrader: (3)

WS6 store is a sponsor here and has them in stock.
http://www.ws6project.com/user_stor/...d-gasket-040-/
$148.00 is the cost of admission.

If you want to tempt fate you can get some China copies for $50 from Speedmaster http:\\www.yourenginewillbreak.com

Camarokid327

iTrader: (4)

I'm just going to stick with the stock GM MLS gaskets.

Since the heads were only cleaned up (.005) I should be able to still use my current pushrods, correct? (TSP 7.4)