My old W9 motor was 14.1 roller was a little bigger with a 1250 APD carb 456 gear 6500 converter went 117 in the 1/8 so your down on power somewhere are the pistons a dome or flat top with the small chamber heads good luck with your new combo after rereading your post I see your using a dish piston my brother I’ll law ran the same piston in his W8 motor the car ran good but never like it should have when he started to look the motor over again he came up with maybe 10-1 compression not 12.5 like he was told