I've done two swaps to carb and both have the same problem. One is my 89 formula with a new 355 and the other is an 85 camaro ( originally a 305 tbi i believe now crate 350) that is my brothers. I noticed that when you turn the key off, the engines like to run for several seconds then shut down. This is not a dieseling problem for sure and it acts like there is a capacitor or something wired in the ignition circuit that delivers fire until it dissipates. Has anyone else come across this? I'd like to know why it happens since i'm sure tech at the track would have a fit about the car taking 5 extra seconds to shut off.

 

post a video. that way it will be alot easier to tell.