440 running weird

My 69 Ply 440 4 speed is doing something odd. when driving around 30 to 40 mph the car jerks back and forth, kind of like a weird power surge. it was not so bad last year but has got worse. I had the AVS carb rebuild last fall and the car ran great, so good in fact I got on it and broke a motor mount.

Put in new Mity mounts this spring, and it seems worse with the jerking, but I would not think that is my issue. after installing the new mounts, I drove it a bit hard and the power is not there that was there last fall. when I floored it it kind of bogged down and back fired just a little bit.

Any ideas what is going on ? Thanks

still have last years gas in the tank ?

Yes, its 105 oct leaded prem and I added stable before I stored it for the winter, never had a issue before.

Did you take any plug wires off when you changed motor mounts? You might have switched a couple of them.

I did not do the work myself, I will have to ask him next week if he took any off, but would think with the lengths being close he did not mess that up. I will check it out when I am off work myself later on.

You might plumb a gas can in the eng compartment to the pump inlet & see how it acts with fresh gas. I would check the plugs and possibly opening up the carb top for a visual. Holler how it turns out

Got the car in to be checked out by my Mopar expert, the choke was messed up, it was stuck so the car was running very rich. he said I was most likely getting 6 mpg when it should be about 15.

I never woulda guessed. Glad you got it squared away

And along with the messed up choke the timeing was advanced big time.

My guy said if I had not been running racing gas the motor would have pinged like crazy, he said its running great now, gonna pick it up today.