dirt track street stock rules state: stamped steel rockers only, no guide plates, valve spring must be stock diameter of head being used, stock cast iron intake and exhaust, hydraulic cam, 500 2 barrel holley, max. overbore .040,o.e.m. crank and rods to block. Have 69 windsor .030 forged TRWs. Want to know compression ratio if GTP's heads were used. Also other piston, cylinder head combos that I could use?