cheap heads-free 340 heads on a 360

The 360 in my 73 Duster has the stock bottom end with J heads that have 1.88 valves. I did some minor porting to the heads to gasket match and clean up the runners. It has a Edelbrock RPM Airgap inake with a Holley 750. Comp cams XE268H cam and springs. Heddman block hugger headders with 2-1/4" dual exhaust. I didn't dyno it because it was just a throw together motor but it goes like a cat with it tail on fire. The car is a 4speed with 3.23 sure grip.I raced a 68 GTX 440 4 speed that was running 425hp and by the time I shifted into 3rd I was a car link ahead of him.