Quote:

the port on an indy head is longer making it hold about 40-45 cc's more than std,, putting your 285cc chapman heads at about a 325-330 indy head.


jeff



That's always been the problem when trying to compare ports based solely on runner volume - it doesn't take into account the length of the runners, which can differ substantially between two heads. CSA is somewhat more accurate as a comparison tool, but still doesn't give any indication of flow quality, swirl and tumble, etc. I just wanted to make sure that I didn't under-port the engine and choke its potential, or over-port it and lose throttle response.