Dual 425 impco setup

[bilgebill]

Franzh, I have recently installed a dual 425 setup in place of the original 300 setup in hopes of more top end. I cannot get the tuning right. Is this too much for my stock 88 454? Should I go with a single 425? And could you explain wether the center screw or outer screw is the max power valve. The engine seems to have no power now(possibly too much flow.) And it backfires upon acceleration. I advanced timing to 12 degrees btdc. Was worse at 4 degrees. It has stock distributor. Should I have gone with a vaccum advance? Thanks for your advice.

 

[franzh]

Bill;
I would rather answer this question privately, since it is not of an engineering nature and addresses a specific application. It is sort of off topic for this forum.

franzh (the @ symbol) texas dot net