how many cc's can you safely cut it down to on a mild open motor. This would bee assuming 0 pop up and stock head gasket. This engine is being built for a backyard track so no rules but it needs to start off as a stock head. Billit is not allowed.
I have.045 off my W/F head and it cc's out to 14. I know guys who have taken .060 off thier Animal heads though. However, I will tell you that going from .030 off my W/F head then to .045 made no seat of the pants difference at all. Compression helps no doubt, but to a point.
IMO more cam, valve springs, (and a billet rod) in order to be able pull more RPM out of your engine along with lower gears is the most bang for your buck. Lower gears pull much harder out of the corners, and then ya don't run out of RPM... Depending on how far you'll want to go you'll need a bigger carb too. Lots of guys on here can sure help you out with matching parts together to make your back yard track a RIOT!