[blykins]

I ran a Probe dished piston in my 425W. It was a 22cc dish and they do offer it in .040" overbore. With a 60cc head (and my other build characteristics), it gave me 10.3:1...which is very doable with aluminum heads and a cam with a decent duration. I also ran a 6.2" rod.

If you're wanting to run pump gas and use the Probe pistons (they're a lot cheaper BTW), you should probably go with the 35-771-8 cam. My CR calculator says that with a 4.040" bore, a 4" stroke, 58cc chambers, and Probe pistons with the 22cc dish, that your SCR would be at 10.36:1. I guessed at your deck height and put the pistons .005" in the hole.

The DCR with the 771 cam would be 8.2:1 running it at 110/106.

IMO, the 35-771-8 cam would be a little better match for the combo and for the car. You could very easily run pump gas....probably 89 octane with that DCR. I would guess that the hp peak would be at around 6300-6400.

If you used the 770 cam, I think you'd have to find another piston to get the DCR in the right spot to run pump gas.