I posted this in the regular LS1 section, but perhaps I'll get a better answer in here?

My heads are on there way here and I'm holding off on head gaskets to check P to V and make final gasket selection based on that clearence to maximize my quench.

Well here's were I'm at;
The heads are 62cc 5.3 heads with 2.02" intake and stock dia exhaust Manley pro-flo valves. The cam is an F14 so things are going to be tight. I can get a set of stock MLS gaskets (still be checking P to V) and be ready to assemble or I can wait until I measure and then order gaskets...possibly being able to go with a thinner Cometic or Fel-Pro?

I was shooting for 11:1 CR and if I use This calculator I come up with 11.3:1 with .054" gasket. If I use This calc I get 10.8-10.9:1.

I'm not as conerned with CR as I am with quench. All these numbers look good on paper, but what is the reality of performance gains versus the extra headache I'm creating?

I'm really thinking about just getting a set of MLS gaskets and not make things more difficult than need be.


What are some opinions of the group here?

 

What is the deck height of your pistons?

 

.010 is a big difference when talking about head gasket thickness and PTV clearance.

Don't use that second calculator because it does not take in consideration the actual deck height of a Gen III engine which is usually a negative number between -.007 and -.010. I found this one to be the most accurate.

http://www.rbracing-rsr.com/compstaticcalc.html

 

Yeah, the second one I added the volmetric displacment of the piston out of hole as a piston dome.

I guess it all boils down to NO SHORTCUTS. If I'm going to the trouble of doing it I might as well do it right.

Maybe I can buy a set of .045" gaskets and a set of OEMs so I can keep working. Whichever ones I don't use I can sell in the for sale forum.

My basis is that Allan Futral told me I could run an F14 on 5.3 as long as I didn't mill them more than .010" MAX! We milled them .007" so I'm thinking the chances of getting away with a .040" gasket are very slim (pardon the pun). It will depend alot on the valve job and how deep the seats which brings me right back were I started...won't know until I measure.

I'm also not sure if the heads are 98 style with the notch which makes all this moot as they'll require MLS gaskets anyway. I know they're center bolt pattern. They should be here in 5-7 days.

 

.010" difference in head gaskits will cause 2cc difference in the combustion chamber in your heads.

 

I agree with you guys, but I'm still wondering about my clearence. I've got 5.3 heads milled .007" so that's a valve drop of .037" over stock already. Could you run heads milled .037" with an .600" lift cam and a .040"-.045" gasket?

I know, measure and find out.