deathsled

my 66 Shelby. It has a Holley 650 double pumper just rebuilt by the shop. This backfire out the side exhaust happened back in early November 2012 then I mothballed the beast. Huge backfire by the way then stall. Restarted after a few tries. The gas seemed choked on the interstate and then stalled comin off the offramp. The gas tank is new but it is old and never used except for a bit of gas at the restoration shop used to start her from time to time. Rust in the tank? New sending unit and sock. Fuel filter? Lodged gasket material from the carburetor rebuild. Car idles along at low rpm okay but get on it and will stall. It's a four speed with toploader and richmond gears.

Suggestions? (Has the cannister type fuel filter) Yes, I know not correct for 66 but engine is a roller rocker while original sits in my closet for a rainy day.

Gun Jam

Im not really sure what question you are asking but I gathered it runs poor under power and it backfired at some point....

Sounds like perhaps the high speed circuit in the carb is plugged up or its a bad fuel pump or it sucked a valve.

1) do compression test on all 8 cylinder is pressure about identical if yes then

2) check fuel pressure and volume place fuel pump "out" line into glass jar crank engine does it quickly fill the jar and splash fuel everywhere? If yes then

3) clean and Rebuild carb.

-Gun

jlg2002

Check fuel filter for restriction and replace. If it backfiired through tthe carb as well you probably failed the power valve in the carb.