Carburetor Choice

For drag racing as long as you leave with the secondary either fully open or fully closed a vacuum or mechanical secondary makes absolutely NO difference. If you use a vacuum carburetor and the secondary is partially open at the launch it's very difficult to be consistent.

I have a methanol 750 that's a vacuum secondary and it's been used by lots of my customers that want to try methanol or experiment with a vacuum secondary on their traction limited circle track car.

One customer who I can think of right offhand used my carburetor, liked the results and then had one done which was exactly the same except his core was a double pumper. His car ran identical ET and speeds when at the track trying both carburetors back to back which was a good fun test.