I'll be happy to answer that one...knowing that the butterflies do not reside in their bores perfectly perpendicularly means that the butterflies are ellipses and not circles. Through careful measuring, Daddy and I determined the angle that the stock butterflies were in the bores. Then we obtained a piece of round steel bar the exact diameter of the butterfly bores and proceeded to cut/saw the bar off at the aforementioned angle roughly 3/32" thick. No centerless this or grinder that etc. I cannot tell you how many people wanted to re-invent the wheel and come up with a absolutely unnecessarily complicated method to achieve the same thing.
The problem I was having, was that we had hand hogged-out the venturis on the rochester 2gc's we were using as the secondary carbs on a progressive linkaged Pontiac Tri-power. We then bored the throttle body out to match the oversized venturis. The P.O.S. stamped sheetmetal butterflies that a BIG name California carburetor shop made did not seal worth a crud and was acting like a vacuum leak...totally unacceptable! When held up to a light, you could see daylight all around the butterflies!This was what we got, after telling them that sealing was our highest priority! The more perfect sizing combined with the thicker butterflies that Daddy and I utilized really did the trick!...and to think I used to hate math and geometry..ha ha ha!
Last edited by Fasteddie455; 06/14/11 03:13 PM.
