Van stalls when In gear only

Hey guys,
Van idles fine than when I put it in drive or reverse it goes quickly and than stalls out when I'm baking or just sitting with the brakes on. Won't idle when sitting in drive. Occasionally will.
318 v8. Carter 2 barrel carb. 727 auto trans.

I'm also in the process of rebuilding carb, cleaning out gas tank and putting new filter and gasket on trans. Any comments- ideas and things I can do during these process would be awesome.
-toby

air cleaner off,,,,,,,spray some carburetor cleaner down into the carb when it starts to die,,,,,,see if that makes the engine happier,,,,,,,if so,,,,then same test,,,,,do the outside of the carb and all over the intake manifold,,,,,we are checking for vacuum leaks,,,,,,,

I'm reassembling everything right Now- I all let you know

Sounds like a vacuum leak. Back when mopar started using lockup 904 trannys on the slant sixes (1977-1978) they would have stalling issues. I R&R a lot of those, sent them back to Chrysler.So they could figure out the problem. We always kept about 4 replacement trannys in stock.

Spraying in the carb seemed to work but it didn't really work anywhere else.

Also seemed like my fuel boiled out of the vent after shutoff. I'll double check my rebuild. And floats.

I'll keep chipping away

to check for Lean running. You can place a shop rag over the carb at idle. If the idle speed increases, your running Lean. If it stalls/chughs them the rag made it to rich. You can also do this by placing your hand over the airhorn of the carb while it's idleing.

I take it that you got a Carter BBD,,,,,,did you rebuild that carb with new parts,,,,,,,if gas is coming out of the vent on top, you are flooding out,,,,,,,needle and seat aint holding or bad float,,,,,,,if it dies in Drive, look down in the carb,,,,,see if there is a puddle of gas down in the intake,,,,,get us some clues,,,,,,,,,

Ok- these sound like some great clues. I'll be on it tomorrow morning.

I did new parts in carb. Triple checked float levels. It's got a new new needle, maybe sticking?

For some reason in the back of my mind I have suspicions about the distributor. Am I in left field?

Did this just start happening,,,,,,,or how long has it been doing this,,,,did it ever run right,,,,,,,you surely need the points and timing adjusted before messing with the carb,,,,,

Did points(with a dwell) and timing.
It ran fine and then it jut got weird when I went to movel it the other day. Almost out of the blue. It's almost like it feels like the timing keeps changing. Timing Was fine than it shot fire through the carb! Telling me it was firing wrong. I checked all spark lead locations than set timing again. It's been running better but that issue came back.

I'm in the middle of going through everything but was hoping to kind of cruise for now as I was doing.

Not sure how it could "slip"?

Fire through the carb sounds like timing, but did you ever rebuild the carb? All things unchanged from "fine" or "ok" it sounds like a carb problem. Fire through the carb after hard and really rough running if at all when starting is a symptom of being 180 off or off on the fringe. But if you haven't pulled the distributor? And it ran ok but there's a carb problem...

Did you check for vacuum leak like Don suggested?

spraying down the carb is an important test,,,,,,,,if the engine runs better, it means you are running lean,,,,,,,,too much air or not enough gas,,,,,,,are the mixtures screws adjusted correctly,,,,or is there a vacuum leak somewhere,,,,,,,did the engine run better when you sprayed into the carb?

I had a slant six dizzy that the screw holding down the condenser would not stay tight. Start out okay then get erratic. Something to check maybe.

Im along with =Rusty!! Lean/no pump shot or fuel -off idle weak! Id also chech some of the above suggestions with carb spray when ideling. I did have a repair from a customer this year- was a screw that wouldnt tighten up securely on a point set!! varied the dwell/ firing. Customer had trouble with that for 3 years-Previous shops couldnt find it!! Look close & remember its always the small items overlooked that cause the problems!!