I've got a choice between 3.23 and 3.91's. I've run 3.91's behind a few big blocks, but it's a little steep for what I want on the street. I really don't know how I managed to live with 4.10's in my 69 GTX, but I guess when you're 23 you can put up with a lot more than at 63! lol I have seen Speed Pro h405cp pistons with rings, on ebay for $120, but it is only an increase to 8.6 with my open chambered heads. I agree that it's better than 7 something, but will I really see much of an improvement?
Get the h405cp's and and with calculated decking you can get over 9:1. If you really want to wake it up, add some Magnum replacement (EQ) heads and burn rubber!
