Hey guys, I've got a 1979 F-100 Custom with a 289 and a C6 transmission. I took it to my mechanic today and he thinks the torque converter it too small for my setup. I bought the truck restored and with a few additions. And I'm not much of a gear head. Kinda bought it as a toy to spend time and money on. I was hoping someone could point me in the direction of a good size or model of converter would be best. It's not a drag truck, and i'm not looking for it to be. Just want to make sure the horses get to the road.

 

Welcome to FTE, lots of good people here.
If your truck has a 289, it was swapped in. The small V8 in '79 was a 302. No big deal 289s and 302s interchange without problems as long as you pay attention to the balance. In your case that doesn't matter.
The C6 is probably Ford's best 3spd auto.
On the torque converter, I really don't get what he's saying. There's really only one converter for the C6 small block combo (disregarding the hi-stall racing converters).
What was the problem to begin with, why did you take it to him?

 

Thanks for the quick response. I took it in for some PM. Oil, Brakes and such. He seems to think that the converter is not a slow stall. There has been some problems when shifting into drive, and when the powers on. most of the time its pretty smooth.

 

What kind of problems? The two most common C6 problems are the vacuum modulator and the forward clutch apply piston seal. The modulator, cheap and easy to replace. The seal, not so much. The part is cheap but to get to it you need to tear down the transmission.
When the modulator goes bad, it doesn't want to shift from 1st to 2nd unless you do it manually. The forward seal starts out by the transmission not wanting to go into forward gears when cold. It'll go into reverse fine. As the truck warms up it will finally engage the forward range. As time goes by, the warm up period takes longer until, finally, one day it just doesn't go forward.
One thing to do, if the fluid hasn't been changed in a long time or you're unsure of how long it's been. Change the fluid and filter. While you're under there, change the modulator. Check the vacuum line that goes to it for any leaks or damage. If you do change the modulator, they are identified by the color stripe on them. Just use the black stripe one, if they don't show that one, use the green stripe.

 

Just so you know, the stock converter stall speed is somewhere around 1600-1800RPM.

 

A basic understanding of the torque converter might also help. What does a high stall converter do?