Are you using the shims that came with the old Trooper 2.8?

If (1) shim isn't enough and (2) shims are too much, you probably need to get a 'shim kit' for GM starter and try different thicknesses of shims until the shim pack is correct. The shim kit is pretty cheap and any auto parts store should have one in stock.

Try using a combination of shims that's slightly thinner than the (2) shims you're using and see how that goes.

BTW a man trans flywheel from a Camaro definitely won't work on a 3.4 Trooper conversion, and I don't think a Camaro auto trans flexplate would work, either. The only applications that would work correctly are from either similar-year S-10's or the original stuff from the Trooper 2.8.

HTH..............ed