The purple cams seem to love more compression.
My 2 builds using the Purple 292/.509 in my E body 4spd with 4.10's and a 275/60/15 tire.
MP create 10-1 short block with a stock oil pump and pan. These short blocks came with the 292 cam. Added the following parts;
2.02 J heads stock ports/replacement valves.
TorkerII 360, Carter 750, Hooker Super Comps @ 1-3/4 tube into a 2-1/2 exhaust, Thrush Turbo mufflers. Viscous fan. Chrome box ignition.
Clutch was a MP unit, AKA Hays. Pinion snubbed & SS springs.
Est. @ low 13's, no actual track time. This is based on the next build below with tack times.
360 with a zero deck height KB-107+.030 slug on stock con-rods. Standard oil pump in a stock pan, Edelbrock RPM AG intake, OOTB heads and a 750 carb. (All Edelbrock)
MSD ignition, Hooker Aero chamber mufflers, all else the same as above.
Track times were mid to low 12's.
1st run was a 12.7 and I wittled it down to 12.4.
Note the E body is a bit heavier than the A body. I have been to the track and asked all the A body owners what they were running. Of all the guys I talked to that ran the MP create 10-1 ratio 360 engine, there times were pretty good for what they were. A body Joe was right on. One fella with a well gutted but still all steel Duster was in the high 11's with a good feeling he could get to the mid 11's. I don't remember what sta and gear he was running. But it was like my 2nd engine above except the carb which was a modified Holley. Nothing fancy, just all biz. Single seat, cage, no carpet or rear seat.