yes 9.5 is bit hi but can be done i have 8 roots blower engines out there at 9.5 i would back it down some 8.500 to 9.000 yes on the 177 less spinning less heat .same with the CR you start to low to crank up the blower to make up for the low CR some guys just can not get there head round that so you run the blower hard make more heat and beat the engine part there is a fine line but what your shooting for is not hard i would use a good bottom end parts forged parts pistons i use 2618 and 4032 alloy for this build would not matter much i have used hyper as well but i would use forged the 5.7 rod and a dish only comes in a JE not srp other may make it but on the last 383 i did they did not if you go to a 6 rod the part number is 13103 and is 9.8 with 64 cc have to move up on a bigger chamber of head last one i did was a JE and did get what i wanted for cr then pistons are 760.a set