[john]

A ported manifold would increase the chances of creep as it would flow air through it quicker. With the maft setup shouldn't you be able to eliminate fuel cut? My guess would be a kinked or a vaccum line with a hole. Since you checked it already I don't know. You should be able to tune for 19-20 psi though. I was running that before. You would want to set your mbc up to 19 or 20 so it isn't so laggy.

When I was running that, I was in 40* weather and had my fuel pressure raised so I wouldn't fuel cut. I tuned for 0-1 count of knock.