I would open the exhaust up and see what happens
Another comparison for you
I have a 67 Valiant. 360 with stock bottom and 484 cam(I’m told). The rest I know. Aero 2.02 heads, RPM Eddy, 600cfm Eddy carb, TTI headers and HEI coversion.
Stock converter, manual valve body, 4:56 gears and DOT...