HSC are flat-top, and in 30 thou over size, they have a volume of about 30 thou lower than a stock 200 piston. I think it has a 1.500 verses 1.531" wrist pin to piston top register.
The stock 200 has a 6.5 cc dish on top when the psiton is 1.531" tall.
If you go to
http://falconperformance.sundog.net/compcalculator.asp
the resultant compression ratio rise for having a shallower, 30 thou bigger, 30 thou lower, flat top piston is enough for 0.3:1 rise in compression.
Basically, its a safe bet.
If you deck the block 30 thou so there is a stock and safe 25 thou gap between the bottom of the head gasket and the piston, CR goes up to 10.1:1. Remember, there has to be a gap with the piston below the block, or there will be a collison between the piston and head at high revs.
(Only pistons and heads which are relieved to 'dovetail' together when the rods have streatched 25 thou can handle the modern postive deck found in alloy Chevy V8's. There is a real advantage in profiling pistons and chambers, but it is too much work on a cast alloy piston).