Dodge 383 stalls at full throttle

[69dodge383]

Got a 383 from a 67 monaco in 71 Challenger. Motor internals all stock. Has headers, weiand dual plane, holley 4150 650cfm carb. Idles fine around 1000-1200rpm. Idles in drive fine too. When i punch the throttle from a stop or rolling stop car acts like it has no balls. This engine should roast the tire (open rear end) but doesnt. If I feather the throttle it accelerates fine. At top end it backfires through the exhaust like a machine gun. what is wrong here?

Also, I did have a fresh rebuilt 770 street avenger on it that got the same results. So I am ruling out the carb...

[Rolling_Thunder]

I would check your timing and advance systems (vac and mechanical) -

[John_Kunkel]

When i punch the throttle from a stop or rolling stop car acts like it has no balls. This engine should roast the tire (open rear end) but doesnt.

What's the axle ratio. I wouldn't characterize the 383 as a tire roaster in all installations.

[69dodge383]

323 rear gears. I'm going to check my timing in the meantime. Desktop dyno says the car makes 300hp450tq with stock 2brl 383 long block topped with holley 4brl carb, weiand dual plane and open headers. With those numbers I think it should have some kick.....

[green69rt]

I hesitated to add my  on this but you don't seem to be getting a lot of input so here's mine.   Let me count the ways that your engine could act like it does.   Simple thing like a disconnected or plugged vacuum line, hold down bolt on the distributer is loose so it goes out of timing (if it gets bad enough the car won't start.)  Timing chain jumped a tooth.  Spark plug wires crossed up.  distributor cap breaking down and spark jumping across terminals.  These may not all give the symptoms you describe but you have to start somewhere.

When I have a mystery problem like this I go back to the last thing I worked on before the problem started,  Then look aroiund the area I was working in, to see what else I could have bumped, moved, etc to screw things up.

[elacruze]

Is it a points ignition still? If so, could be point bounce. Could be a poor connection in the ignition power circuit, which 'breaks' under load and sparks inappropriately. Could be a fouled plug. Could be a blown power valve. Could be a leaky exhaust system feeding air into the mufflers.

[69dodge383]

I am going to check the timing when I get home today. I think the problem my be that I had the vacuum advance and the manifold vacuum hoses backwards on my holley carb. Hence there was no vacuum advance in play. So that may be the culprit. So I am going to double check the hose connections and reset the timing. Also, the car is open headers at this time, no pipes, just headers. The neighbors love it LOL

If it still gives me probs I may get an electronic distributor. I have changed the points and condenser a while back and set the dwell with a dwell meter.

Thanks for the responses. I will keep you posted

Doug

[green69rt]

I am going to check the timing when I get home today. I think the problem my be that I had the vacuum advance and the manifold vacuum hoses backwards on my holley carb. Hence there was no vacuum advance in play. So that may be the culprit. So I am going to double check the hose connections and reset the timing. Also, the car is open headers at this time, no pipes, just headers. The neighbors love it LOL

If it still gives me probs I may get an electronic distributor. I have changed the points and condenser a while back and set the dwell with a dwell meter.

Thanks for the responses. I will keep you posted

Doug

Oh wait!!!?  You're running open headers?  You really need to richen up the carb jets if you plan on firing this motor up very much.  You can always go back when you get the exhaust system connected.   That machine gun sound may only be the normal sound at high RPM with a cam that has considerable overlap?    The poor response may go away also but probably not.

[69dodge383]

The cam is stock, the motor is a mopar 383 2brl with headers weiand dual plane holley 650 carb.


Im going to mess around with it more tomorrow

Doug

[c00nhunterjoe]

If the cam is stock then why is it idling at 1200 rpm? You have something crossed up.