Never said use LS pistons. I said GSR internals.

I found this online somewhere, looks like it's mostly accurate. However, credibilty is not established.

B16a head and pr3 pistons 11.2

B16a head and p30 pistons 11.4

B16a head and p72 (ao) pistons 9.9

B16a head and p72 (00) pistons 10.5

B16a head and p73 (ao) pistons 10.7

B16a head and p73 (00) pistons 11.2

B16a head and p61 pistons 10.4

B16a head and pct (CTR) pistons 12.2-3ish

B16a head and pr4 pistons 9.5

Add .2 to all to calculate the GSR head with all of these.

Type r and b17a heads have the same combustion chamber so calculates the same.

Source: http://www.geocities.com/teampimports/lsvtec.html