Re: 347 swap, NeeD Help! runs good but dies when i tap throttle
Thats a really cool looking car you got there & as you can see your in the right place for good info.
My old build was just like your motor, with the same cast iron heads that had been cleaned up, but specs on em, i never knew. A holley 670 is plenty for that motor with vacuum secondaries for a street car, easy to maintain, better fuel mileage & mine at least, was near perfect right out of the box. I to chased vacuum leaks, timing issues & as stated above, just try look after one issue at a time. Once i got mine driveable, & to a good shop for a tune, they found a leaky intake gasket on one bank, that was the whole source of all my issues! With a good tune that little motor ran so nice, couldn;t believe what a good tuner got out of it.
good luck & keep us apprised,eh