Bob: I agree. I bought my set up used, and it came with a straight cut manifold. I had it milled for 10deg and the linkage no longer worked. Traced it down to the L & R throttle arms were going through different arcs at different times. I made a temporary fix by shortening one throttle arm and it all worked ok, but I plan on going to a center bellcrank when I can find one. System has been replaced with a 4 barrel set-up due to weber manifold sealing problem. (actually a head problem) on one side. Will be pulling engine for that and
oil leaks, webers go back on when engine goes back in.
Ted