Does your distributor have a vacuum advance? Most Hi-po distributors don't have, which will cost you a little MPG at highway cruise. If not, go for 37 degrees total advance at speed. At light-throttle cruise, most small block engines will handle 45 degrees or a little more of total advance, which goes back to 37 as soon as the throttle is opened up to accelerate.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!