That doesn't sound right. Your timing is dead on, but the ex manifold burns cherry red. Are you detonating at all? You might be running to lean, and you might want to pull the manifold off and clean out the passages they could have a tremendous carbon buildup slowing down the exhaust passage. What size exhaust diameter do you have, is it stock? A friend of mine purchased a 87 efi truck and some fool put on a 1 inch diam. exhaust system (must have got it from a lawn mower) almost blew the motor up past 2500 r.p.m.