Ok, here's the deal. When the car is cold, it runs fine. Accelerates properly and smoothly. It seems that, when it gets warmed up, things get wiggy. If I give it just enough gas to maintain speed, it runs smooth. If I give it a tiny bit more gas, it sputters, almost like it's missing a bit, but still accelerates (barely). If I give it a bit more gas, it REALLY sounds like it's missing and loses power and speed. If I just put my foot down, all engine activity stops. No pop, no bang, no fizz, no nothing. As soon as I let my foot off the gas, it goes back to normal, runs smooth (as long as I don't try to accelerate). :(

The carb is an Edelbrock 600 (brand new) with electric choke.

The intake manifold is also Edelbrock (Performer) and fairly new.

The distributor was changed from points to HEI a couple years before the car got parked, and was running great recently. (For the life of me I can't remember the brand I put in there and the car's not here for me to look at it right now.) The coil is new (ACDelco).

At first we thought this might have been a carb problem, but the way the engine seems to shut down when I put my foot down is too fast to be fuel. It's almost like there's something turning off the spark when I give it too much gas.

As I said, weird. Any help is appreciated.

maybe plug wires? I was chasing a miss in my el camino today and after pulling plugs to regap them and clean them up it ran good but comes back to a miss so I think its not hot ignition?

I had thought of that, but there's no missing when it's idling or cruising, only when accelerating. And when enough gas is given, the engine cuts out completely.

GM HEI??
Try this simple test first. Disconnect and plug the hose going to the vacuum advance canister on the distributor. Go for a test ride. Acceleration may be sluggish, but does the engine miss or cut out anymore?

No?
If this is the case - no cut out or missing: Remove the distributor cap and check the wires/leads coming off the pole piece assembly (the circle with the internal pointed teeth) that plug into the ignition module.

The pole piece twists with vacuum advance, and the wires can fracture just at the point where they enter the pole piece. At idle they're not flexed, and touch internally. Give it some gas, the advance twists the assembly, and breaks the connection. Heat can also play havoc with this item as well.

Unfortunately you have to pull & disassemble the distributor to replace this item. Do the module at the same time.

What are the rest of the engine specs? Really sounds like the carb is lean and you need to tune it, but check the float level first. Edelbrock carbs are easy to tune, just get a tuning kit, post back if you have trouble.

The engine's a 305, nothing added except headers. When it was running badly, it was flooding - or at least that's what it seemed to be doing. Run fine for a while, then not start (turn over and over and over). Leave it with the air cleaner off for 10 minutes, then it would start, and run sputtery for a bit then clean up. LOTS of smoke out the back end. We fixed that by leaning it up. Now it runs great (when running) but has this weird acceleration problem. We just put a new coil on it, so I'm going to run it tonight and see how it goes.