C1 with TH350 or TH400?

[Mark Radin]

I bought a '59 a while ago that had been disassembled. It came with a cast ali Powerglide. I have spent some time trying to locate a cast iron one - so it was like a factory speced unit. Everyone says for a "driver" car I should put in a TH350. I would need to locate one of those. I do have a TH400 in my workshop. Will that work as well as a TH350, and be just as easy to fit?

Thanks,

Mark

[Loren L.]

If you're going to replace the Powerglide,

by all means go past the 350/400 and go to an overdrive automatic like the 700R4 and save a 1000 RPM at 70 MPH.

[Michael L.]

Re: C1 with TH350 or TH400?

Mark, my '55 used to have a 350 in it. I'm putting a 265 V8 and a cast iron Powerglide back into it. The 350 fit with no problem, mounting brackets will have to be fabricated, a plate was all I needed on mine to bolt to crossmember mount. The output shaft has more splines, I think 27, so a new yoke is in order. The shifter will have to change as well. Length will differ depending on what the 400 or 350 came out of. Measure the casing on the aluminum trans and then the 400, height, width and lenght. It should fit. Flex plate may have to change as well.

Mike

[Roy B.]

Re: C1 with TH350 or TH400? mike is right *NM*

[Joe R.]

Re: C1 with TH350 or TH400?

Hi Mark:

For a driver I would definitely put in either a 3-speed or 4-speed automatic instead of a Powerglide. First gear will be much more responsive and with the 4-speed automatics, fourth gear is an overdrive gear for highway cruising.

I believe that both the TH350 and a TH400 3-speed automatics will fit in your car, but the TH350 is a few inches shorter and is much closer to the length of the original Powerglide. In fact, I think that certain versions of the TH350 can be directly substituted for the Powerglide.

Among the 4 speed automatics, the one that is the closest to the size of the Powerglide is the 2004R. The 700R4 is a little stronger but is larger. As with the TH350, I think the 2004R can be directly substituted for the Powerglide.

I think you will find some useful dimensional comparisons at www.tciauto.com and some Corvette conversion kits (at least for C2 Corvettes) at www.bowtieoverdrives.com.

[Dick W.]

Re: C1 with TH350 or TH400?

A 200R4 will handle a fairly healthy small block with ease. It just needs to be updated with clutches, valve body and a good converter. Very easy installation