Truck won't start right up and backfires like crazy!

[naystcb]

I have a 1971 Chevy Cheyenne Longhorn with a 396 and an edelbrock 1406 w/electric choke. My buddy and I recently installed an HEI distributor and new plugs(gapped at .045) and wires(8mm). Before installing this distributor the only issues that I was having with the truck was that it was missing and seemed to lose power and bog down and then stall for no reason while driving at cruising speeds on the freeway. I would feel it start to bog down and try to give it more throttle to keep it from dying but it would just die and then as soon as I would restart it would be fine again. So we changed the distributor and the only other change I made was that I bypassed the old fuel solenoid that was located underneath the bed of the truck that regulated the fuel from the two reserve tanks which are no longer installed.

Now the truck won't start up, I have to pump the accelerator and fight thru backfiring until I finally get it started and then I have to keep my foot on the accelerator to keep the idle up until the truck warms up and then it will run ok. It almost seemed as if the electric choke wasn't working so I replaced it but it still requires the same actions to get the truck started. The last time I started the truck which was about an hour ago it made such a loud explosion that it almost felt like the truck was gonna blow up, in fact I think it destroyed my mufflers because now the truck sounds like I'm running straight headers. We have tried restabbing the distributor many times and I currently have the timing at 10 ATDC but whatever we do it all seems to have the same result. Hard-starting and loud explosive backfiring. Sometimes flames will shoot out of the carb...we're baffled! I was thinking that the carb may be bad.

The truck ran fairly well before the HEI, it just had the loss of power and stalling out while at cruising speeds but it would always start and run at a nice idle. Now the truck won't start up with out a fight and when it does get running it seems to run fairly well but I have noticed a slight bogging when I shift into third. It is a stock 4-speed. Please help with any ideas of what could be wrong. I will try to take some pics of my set up and see if that helps with any suggestions you all may have. Thanks.