My old pump gas Duster ran 10.69 ET at 124. MPH with the original set of ported big valve 906 heads, swapping the heads to a set of MCH CNC ported Eddy RPM heads picked it up to 10.40s at 127.MPH. I ended up swapping out the 4.250 stroke crank to a 4.300 to raise the compression ratio from 9.25 to 1 to 10.3 to 1 and that help it run in the 10.30s, the final change to that motor was changing the heads again to a set of Indy SR M.W. ports with a single Indy 400-3 with Holley 1050 CFM Dominator. The heads where 9.0 CC smaller than the Eddy RPM so that raised the compression ratio up to 10.8 to 1.
Those changes ended up with a best of 9.993 at 134.8 MPH with the air cleaner and full exhaust system on and hooked up