Reply to "Street 403C on the Dyno"

> I seem to think that the A3 head exhaust ports flow significantly better with a 3" radius tube on it?

You may be recalling flowing with a 3" long straight pipe stub.
A head like an A3 will pick up 30 CFM on the exhaust with a pipe
stub versus a bare port. Most of the advertised and magazine
flow data you see will be with a pipe stub. However, the flow
bench data I've gathered on my high port heads has been with a
bare port. I think if I flowed them with a pipe stub and used
that data in Dynomation when I design a cam it will result in a
shorter exhaust duration.

Dan Jones