"Dragsix" has better information on stovebolt distributor setup from his work with a Sun distributor tester than all of the above "cut and paste" information from a guy with no hands-on experience at actually making these engines run right. You can dial in a distributor advance curve pretty easily with a delay-flash timing light and a tachometer if you don't happen to have a Sun machine handy. The combination of initial and centrifugal advance should be somewhere in the mid-30's, with an additional 8-10 degrees added by the vacuum advance for light-throttle cruise. Once a load goes onto the engine for hill climbing, passing, trailer towing, etc. the vacuum advance drops off and does not enter into the total until the load goes away again. One degree of over-advance will cause as much of a power loss as 4-5 degrees of retarded spark from the optimum advance point, so always err on the side of "not enough". I've got hundreds of hours of dyno run experience on all sorts of engines, and that fact is pretty much universal, no matter what engine is being tested.
Jerry
