I have a 61 ford Galaxie with a big block 390......She starts up fine and idles with no problem.....She does seem to backfire a little when you first start to drive around..but..at low speeds/RPM's she loses power when you accelerate...run pretty rough..will get a huge and loud backfire..

We went a on a Christmas light cruise through some neighborhood the other night it would backfire like someone shot off a SHOTGUN!!!!
The car stalled a few times too..but started right back up....at the slow cruising speed she ran like crap..If we stopped had to put her in park to keep her running...

Now once we get up to speed..like on the freeway or whatever...the car ran fine...no loss of power or backfiring....any thoughts????????????