My brother bought a '81 chevy with a bad engine. Then we bought a '74 Chevy with a good engine. I swapped the '74 engine onto his '81 Chevy and used the '81 HEI distributor. It has a Quadrajet carb on it.

Now the problem is that when you start the truck, it will barely run. YOu have to keep it to the floor and it sems as if its running on 4 cylinders or something. If you let off the gas, it will die. After holding it to the floor for about 15 seconds, it will clear up and run OK. But when you get going down the road, it sometimes goes back to the original problems.

The engine seemed to be running good when in the '74. However, the tranny was bad so we couldnt drive it. But it started right up and ran great.

So far we have replaced the plugs, wires, cap, rotor, fuel filter.

I was thinking about tring a different carb. But remember, it seemd to be fine before. although sat for about 4 months before we bought it.

AND when I put my timing light on #1 plug wire, it reads funny. Not uniform flashing. Other wires are OK. This leads me to beleave a faulty coil. I bet they are spendy, so I would like your opinion before we buy one. I have a standard (non HEI) distributor, but that is ALOT of work to do just for testing purposes.

sounds like a timing/fuel delivery problem to me. whats the fuel pressure reading? have you opened up the HEI to visibly see if there is anything broken? your description of the timing light sounds like there might be a culprit somewhere there. good luck with it.

oh, check the coil too. did you use the coil for the HEI dist or a different one? i believe the HEI coil has a higher output, so that may be a problem too.

Sounds like it's flooding, when you hold it wide open you flush the cylinders with air, and then it clears out. Ck the plugs to see if they are black with soot. Tap on the carb with something to free up the needle and seat, look down in the carb to see if it is boiling over when you shut it off.

I willing to bet the timing is off. Pull #1 plug and bring piston to the very top. Make sure timing mark is on or near the correct timing mark. NOw check that the Rotor is pointing to the #1 spark plug wire and is going to # q cylinder.

One common problem is the factory timing gear (the upper one that's on the cam) has some sort of plastic/teflon teeth that get brittle with age then break off thus messing up the timing. Check if the rotor turns in nice tight synch with the crank...just turn the harmonic balancer by hand and watch the rotor for lack of smooth movement.

A vaccuum leak is easy to check, take a small propane torch with a piece of vacuum line attached, run the engine and pass the propane fed vacuum line (not lit :D ) around the intake manifold where it meets the heads and near the carb base, ect... If your idle changes you have a vacuum leak.

A flat lobe or two or a bent pushrod can be checked pretty easy too. Pull the valve covers and watch for rockers that noticably do not lift as much as others. You know it needs valve cover gaskets anyway :D

A compression check would be a pretty good idea too.

HEI's aren't too often the problem but I've seen a couple bad one's.

A quadrajet doesn't like to sit long periods either, they are great when right but suck when in need of work.

Good luck with it, post what you find for us curious type fockers :flipoff2:

The timing is good. I set it to 8 degrees before TDC. and I checked TDC twice before I fired it up and then 1 more time after just to be sure.

I replaced all the gaskets (oil pan, intake and valve cover) but They are rubber, so I guess I can check the rockers.

I will try switching carb tommorow.

Thanks for the advice. I will see what I come up with.

I hope I get this thing running good soon. My brother is starting to HATE the truck and wanting me to hurry up and fix it. And I am tired of working on this truck and the rest of his junk for free. :mad:

:nuke: