My 512 C.I. pump gas low deck 906 head(mildy ported with 2.14 int. and 1.81 exh. valves, no magic in those heads) 400 block stroker with a low deck sixpak setup made 612 HP at 5500 RPM and 644 ft lbs at 4500 RPM on CA 91 0ctane pump swill years ago. It ran 10.69 at 124.7 MPH on 91 octane Oregon pump swill at Woodburn through the comnplete 3 inch exhaust and air cleaners on weighing 3450 lbs with me in it.
That combination exceeeded my expecations by far
There is nothing wrong in using what you have as far as I'm concerned
I ended up turning that motor into a real street beast by swapping parts around on it, every time I put a better set of heads on it(I put a set of Eddy CNC ported RPM on it after the 906 heads, then a set of Indy M.W. SR with a Indy 400-3 intake and a Holley 1050 CFM Dominator carb and finally a set of Indy CNC ported big valve 440-1 heads that flowed 370 CFM at .700 lift with the same intake and carb. as the SR combination) the car ran faster and quicker, Mopar wedge motors love more air and fuel