I'd run a bigger cam! if you can put a K-1000 or K-950 then you can get up to .700 lift pretty easy. I wish the bore was bigger but it would not stop me from trying it with parts I had laying around. Lighter pistons can turn more RPM. That crank is not super huge so I'd shift it at 7500 if that's what it likes. I think it will still shift under 7000 but I am not positive. I'd go .270 or bigger at .050 and a big stall. 5500 or so.