Purple Shaft vs XE Comp Cam

I was focusing more on the differences of the two cams. Currently I have a 71' 340 Duster. About 3000lb with me in the car.
Stock block, bored .03, 10.5 to 1 comp,
3 angle valve grind,
4-speed, centerforce pressure plate, 3.91's (soon to have 3.23's). Primarily street car.
LD340 intake, 850 thermoquad,
2.5" pypes x-pipe w/ cutouts, Dynomax Ultra Flow welded full exhaust.

The car as it sits will do 13's.....have yet to tune it exactly.. But I have heard nothing but good about the comp cams. If its something that would noticably increase my HP or times then thats what I would like to know.

If going MP use the .528 solid 284* 241*@.050 112cl

I had the same setup but with .528 solid/750 holley and it ran like a bat outta hell!