Bore is 3.900 gasket is 4.060 @ .05 thick
Volume is .050014 in sq = .8195cc (too much)
I'll just put them on the shelf and use some
Other time ! Time to order something else now

 

What are you saying here? The gaskets are too thin, too much compression? Too thick, too little compression?

The fact they are for a 4.000+ bore is fine on the smaller engines as far as that goes. Those gaskets have been used on 5.3 and 4.8 engines time and time again.

 

LS9 head gaskets are real good on 5.3 and 4.8 setups. Thats what I mostly see on those motors under boost.

 

Yea in theory, the ls9 head gaskets aren't the right choice for us 4.8 and 5.3L guys. But I run them and haven't had a problem. I'll be throwing 22+ psi at them.

 

Same here. I run them as well with a set of head studs. Sees 12-14psi all the time

 

Well I'm saying that with a 3.900 (LS1) bore these
Will drop cr .8 (almost) 1.0 cc.... Which is good
For stock engines to lower cr but building a
Motor with 9to1 using ls9 gasket won't be 9to1

 

Your thinking is flawed, Yes the area of the gasket opening is .8 cc, but you forgot to take into account the area of the gasket it is replacing. You're only opening the bore size a .160, which is very minimal difference between the 2 gaskets.

Running the numbers on a compression calculator between the two gaskets, a 3.900 bore gasket and a 4.06 bore gasket of the same .050 thickness, yielded only a .1 drop in compression. My example went from 10.16 to 10.06 just changing the bore size of the gasket. Not almost full point like your implying

 

I use these as well with no issues so far. There are probably better options out there (in terms of the bore), but these are affordable and since they are from GM they will be high quality.

 

Ok hair dryer man,now my flawed thinking wants Me to cc both 3.9 and 4.06 gaskets .that will yield the answer ! but for now .8 is .8 however If you were to cut me a good deal on a hot pipe kit I can over look this hole thing .... Cheers

And by the way took your advice bought an s480 instead of pt88 but don't
Let that go to your head tho with you and your calculator

 

I always cut good deals! There is a reason the fast guys are running my stuff.