Looking for more off the line punch from my 400/ TH 400.  Local car show guy said swapping out stock convertor for a smaller one out of a lighter possibly FWD car would cheaply and reliably increase stall speed.  Also, he said, it would slip less than an aftermarket converter becasue it is smaller.  I dont understand?

Car is a 68 FBird 400 16x heads, 750 Holly on Edelbrock, factory exhaust manifolds with duals, RAIII cam and (I know, I know) a 2.73 rear.  

Any input on the converter?  

a quick and inexpensive swap is a converter from a BOP turbo 350. I think its an inch smaller and a couple of hundred rpm higher than the 400. check my car on readers rides. i have a turbo 400 with a 10" 3000 stall, because of the cam,intake,and rear.the other option is a bigger first gear in the 400 but the part is $$$ and you must rebuild the 400.  

If you just look for more power out of the hole I would lower the gears in the rear end instead of a higher stall converter.  

First problem with the local car show guy, is that no front wheel drive torque converters will work with a th400 or th350.  Years ago it was common to use the tiny converter from a 4cyl Vega th350 in V8 powered cars as a cheap high stall converter. The end result is still the same as a true hi stall converter. The problem with a higher stall in your car is that the rear gears you have will make the converter slip all the time, even when cruisimg, which will cause overheating of the trans and fluid, leading to damage. Pontiacman is right you need more gear. I would go with 3.42 or 3.55 gears depending on the tire size you have. You will think you suddenly found another 100hp!
Steve  

Thanks all

So can i get 3.42, or 3.55 gears  (and a posi-type unit) into my stock open BOP 1968 rear( currently open with 2.73s).  I know there is some discussion with the 8.2" BOP rears of my vintage and ring gear size.  Any advise?

Rich  

Summitracing caries posi units for that rear as well as the ring and pinion gear sets.