This is my first time putting some head gaskets on and I had no Idea there were so many differnt thicknesses.. Im putting l98 heads on a 93 tbi block witch is the same as the l98, But what thickness do I need?
Thanks

Also My setup is going to be stock 350 shortblock with l98 heads (same compression as stock l98, with a 279 thumper cam air gap intake and quadraget carb with 1 5/8 headers. Anyone got a clue to how much HP it might make? Hopefully more than a stock l98

 

0.021 compressed thickness. That'll maintain the L98 compression, assuming the pistons aren't dished or domed. The heads are going to be holding you back from everything else. I'd say you'll get anywhere from 280 to 300 flywheel hp. (Stock L98 = 245 IIRC)

 

I figured the l98 heads would not make much power but there better than the swirl port truck heads that were on this motor.

 

0.021" won't work if the TBI block has been zero-decked. You need a straightedge and some feeler gauges, to determine how far below the decks the highest parts of the pistons are. Then choose a gasket thickness that gets you as close as possible to 0.040" piston-to-head clearance. If you find you have several choices, choose the gaskets with the bores closest to 4.100".
And yes, these heads are better than the swirl-port TBI heads, well worth the hassle.

 

The pistons look exactly the same as the l98 ones Ill try and do what your talking about though.
thanks

 

Using head flow data on TGO this is what DD2000 came up with.

 

I think your simulator was pessimistic, unless it was giving rear-wheel results with a manual trans and synthetics.

 

wow thats seems way high. Unless the stock TPI intake really is THAT restrictive.
I know just swapping a HSR will give what?? 30-40hp? And thats still with stock cam.
so a carb and cam might be over the 300hp mark maybe..

 

What TPI? You can't use a Thumpr with any production EFI. With an RPM AirGap, 400 HP is entirely realistic, even considering 9.2:1 and B2L heads.

 

im not using efi im running a carb.
I was just comparing going from stock tpi setup to cammed/carb swap setup

 

Fel-pro 501SD should be just fine for a head gasket.

 

IF it's 0.038" thick or thicker, it's probably safe, but since the OP has a chance to get it right, there's no point in settling for "probably safe". Because if the end result is the piston smacking the head, then even free gaskets are a bad deal.