[John Brown]

No matter which vacuum advance can you use, the vacuum advance drops off the second you hit the throttle. It comes back at cruising, but it's gone the instant you jump on the gas. If there is no bushing (rubber or brass) on the pin that goes into the distributor advance cam slot, I suggest using the brass bushing from a MR GASKET advance curve kit as that limits mechanical advance and allows more initial timing to be used. The extra initial advance normally makes for improved throttle response.