Carb keeps catching on fire!

[Syco67]

I am getting ready to help my friend swap a 350 from a 73 1/2 ton truck in to a 78 1/2 ton truck, but we are worried about the condition of the engine, it was running fine, then my friend sold it to his neighbor, then bought it back a few months later. he had gotten rid of the edelbrock carb (traded it for drugs) and put on a jimmy-rigged Q-jet from an 80's model camaro, every time we try to start it, it will start to run and then begin popping and shooting fire out the top of the carb. None of the valves have dropped, and the engine doesn't make any other noises. This guy had a habit of starting the engine cold and flooring it until it warmed up. We are hoping the carb is the problem, but don't have another one to swap and check. What else could we check.
TIA

[Grim Reaper]

Timing is off. Bet the distributor is in backwards.

I would take the beat to death Quad over a Edlebrock (carter) any day.

[78chevstepside]

It sure wouldnt hurt to pull a plug and cap and check if the distibutor is 180 degrees out. generally back fire through the carb is a ignition problem. I bet the carb is the problem. Maybe a puter controlled quadrajet ?

[Grim Reaper]

Originally posted by 78chevstepside
It sure wouldnt hurt to pull a plug and cap and check if the distibutor is 180 degrees out. generally back fire through the carb is a ignition problem. I bet the carb is the problem. Maybe a puter controlled quadrajet ?

Ohhh I didn't think about that. Yeah if it'sa CCC it will have Reostat on the throttle linkage with 3-4 pin plug. It will also have a 2 pin electrical connection on the front passenger side top. If it has either of those it isn't going to work.

If it has just the 2 wire connector then you could get it to work with a temp sender from the correct year car. Just need to trace the wires to the carb to the sender on the intake. Even so I would scrap that. The last of the good Quads were about 81. Electric choke and nothing else.

[swervin ervin]

Sounds like he may have stuck a computer controlled carb on there too. The 80's Carmaro's were computer controlled to where ours wasn't. But I agree on the timing being off too.

[Syco67]

The carb has a few electrical ports on it, we don't intend to keep it though, certain parts of it have been mangled pretty bad. I don't think this guy would have messed with the timing, he was pretty darn lazy, but he is also one heck of a liar. Would the engine run being 180* out, because the engine still runs, it just shoots fire at the same time. and makes a popping noise, the exhaust sounds fine though. Which piston is #1 so I can check the timing?

[Free88]

It could be that due to his habit of revving the engine he may have caused the timing chain to jump on the sprocket. May have broke a tooth off the timing gear. Some of these old motors had a plastic cover over the crank gear and these were natorious for breaking off, causing slop in the timing chain. When revved the chain would jump causing the gear to slip aand throw everything off. This is my experience.

[swervin ervin]

After reading this again, it's highly possible you have a broken valve spring.

And no, it won't run if it's 180 degrees out.

#1 is drivers side, front.