Hey all,

odd situation that I have never experienced.

Here is the combo for information.

Warmed over 440 with 10:1 cr, MP .474/280 cam eddy performer RPM intake and headers. real basic driver motor.

Cope Racing, Brand new on the shelf for a year or so, super street 727

converter is a used stock unit out of a 73 440 road runner

3.54 gear 30 inch tire

1966 Plymouth Fury III 4300lbs with driver

Ok Idleing at 1100, I put the car in gear and it loads the engine like to 5-600 rpm almost stalls while I hold the brake, if I let off it will drive away, I mean it pulls like the engine is at 1800rpm.

what could cause this? bad converter?

Converters often get the blame in situations like this but it's usually the engine tune at fault. If you hold the brake with your left foot can you throttle up past the idle speed?

Well, it will push through the brakes and it seems like I'm staging for a race

If the convertor were locked I'd think it would stall the engine if you had your foot firmly on the brake or be making some gawd awful noise as it was eating it self into a million tiny shards ...

I apologize for not being clear enough. It feels like the converter is engaging as soon as the motor is running. I didn't mean literally locked up.

A stock 11 or 12 inch converter will try to stall most engines

with a cam like that.....they're too tight for that application.

Could possibly be the converter sprag has failed, that and you probably need a higher stall speed for the cam you are using.

I think a lot of it is wrong converter and likely tune up.

The vacuum advance needs to be on ported vacuum. BUT it should be unhooked first while you get all tuning done.
You probably could use 1 light advance spring in the distributor.
That cam should idle well at 800 in gear with vacuum advance unhooked for now.

What I think is happening is at 1100 you have carb turned to far open probably because not enough idle advance but when you pull it into gear and vacuum falls off as does the advance needed to keep idle.
Carb/carbs are probably to far open to get good idle circuit signal as well.
Then the tighter than needs be torque is making it a bit worse.
but when you let off brake some load is taken off engine and it wants/is allowed to accelerate to where the carbs are set open to as rpm comes up so does vacuum and advance all increasing power.

So if you are on manifold vacuum that is the first thing to eliminate and down the road maybe hook to ported vacuum to try improving slightly cruise gas mileage.

Second thing to work on is idle advance and total advance (with vacuum advance unhooked and port plugged)
That cam will want in gear idle timing of 16 to 20 and still maintain 36 to 38 mechanical total.

Sounds like it's time for a ptc 727 9.5".

thanks for all the info, I gave the engine a bit more advance at Idle and dropped the idle to 850 and it still pulls. not as hard but I am sure its the converter.

I guess I learned the hard way to not assume the used part is what was told to me. I shouldnt believe my lying eyes.

I saw the car and combo the converter came out of (I thought) live and learn.

going to call John Cope for a PTC in the next week or so.


henry

Mistakes give us something to talk about!