When I'm setting up a HEI for round track racing, I restrict the centrifugal advance to about 8 to 10 degrees less than usual, and add a corresponding amount to the initial timing. The small block V-8 works best with a combined initial and centrifugal advance of 36 or 37 degrees. I put in about 24 degrees of centrifugal, and set the initial timing to about 12 or 13 degrees BTDC. This gives batter acceleration than the standard initial timing of 4 to 6 degrees without over-advancing at higher speed. The centrifugal timing should max out at about 2,500 RPM, which is controlled by spring strength. Vacuum advance on a street engine adds about 10 degrees at light-throttle cruise for fuel economy.
Find a set of distributor specifications for the stovebolt engine, and adjust the HEI as close as possible to those specs. The above numbers work for 283, 305, 327, 350, etc.
Jerry
