Powerglide to TH350 swap questions

Hey guys, I'm putting a TH350 in a 1962 impala which previously had a cast iron glide. My TH350 is a long tailshaft (8" instead of 6"). I know that an aluminum glide and a short TH350 are close enough in length to not require reworking the driveshaft. I'm also pretty sure that this long TH350 and an aluminum glide only differ by about 2 inches. When I measure what I need to do, I'm finding that I need to shorten about 4.5", does this sound right? Does anyone know if a cast iron glide is shorter than an aluminum one?

Thanks

 

I'm no expert but I do have a couple of long shaft th350's. I believe the tailshaft is 9 inches long on them. The will swap length wise for a 700r4, by moving or changing the crossmember. So 4 1/2 inches sounds a little off to me. I'd guess it's closer to 3, providing the glide is the same length as a 6 inch th350. Rather than hacking the drive shaft, you might see if a trans shop could shorten the tailshaft.
Good luck!

 

I think the iron glides are a big shorter, so 4.5" does sound about right. I hope you have the trans installed and the car sitting level before you start measuring for the driveshaft though, that way you'll only have to get it done once.

 

Well that's good to know, it sure does seem like it would be shorter than an aluminum one based on my driveshaft (I don't have the iron glide to measure).
Does anyone have a cast iron glide they can measure for me?
The car is sitting at ride height, and I made my Dad measure with me also rather than my usual measure once, cut twice, that's a little difficult to do when shortening.
Thanks for the help.

 

Besides cutting the shaft to the right length, don't forget you will have to change to a fine spline front yoke and either make a new crossmember or extend the trans mount back also.
I did a 63' Chev cast iron P.G. to TH350 swap a few years back, but forget what the yoke was out of.
Maybe someone else can help.

 

Yes, the cast iron glide uses a coarse spline, I changed it out already. The crossmember bolted right up.
Blasted, that sounds like what I'm seeing (plus adding the 2" for my long tailshaft TH350).
As information, about 15 years ago we put a long TH350 in place of an aluminum glide and had to shorten 2.5". I've always been told that a short TH350 and aluminum glide are close enough in length to work (no shortening). There just seems to be very little info out there on cast iron glides.

Thanks for the help guys.

 

I've owned ten 62-'64s since 1973, Glides out of full size X frame Chevies whether Iron or Aluminum are 1-1/2" shorter than a short shaft TH350 or aluminum Glide out of '62-Up Chevy II or '64-Up Chevelle. The later short shaft aluminum Glides, shortshaft TH350 and 200-4R are all the same length and also the same length as the 4 speed setup in the X-frame Chevies. My friends have done the 200-4R swap in a '63 and '64 using the Al. Glide stock shaft as it was also a fine spline and since the front part of the shaft doesn't move much there is no binding issue but the 4 speed driveshaft works a lot sweeter if you have access to one. Go with what you have you'll be fine.

 

so this is an old thread but I just did a iron-glide to th350 short tail conversion, and I spent a lot of time looking it up before I did it and found a bunch of contradicting info. So here's how it worked for me:

this was a 235 straight six with ironglide to sbc w/ thm350 swap. this was a 62 impala.

we pulled the 235/pg out together, and put the sbc/350 in bolted up as well. The side of the motormounts that where on the frame that where in it would bolt to the sbc but nothing else really lined up very well. very tight in the tunnel, would have needed a new crossmember fabbed. I have a copy of the factory assembly manual, figured out there where different v8 brackets, so we got some of those, then it all went in easy, thm350 mounted right up to the crossmember like it was mean to. Then we had to get the driveshaft shortened (just the front part of it) and get the appropriate splined slipyoke on it.

the shift linkage needed to be partly fabricated but it wasn't complicated, but since the pg was 2 speed and the thm350 is 3 speed there's no detent on the shifter for getting into 1 ( so D is 1,2,3, and the 1 that's marked on the dash is actually 1,2). I guess there's some parts for the column that will make this work out.

 

mugurpe, Thanks for updating that post. I'm in the same boat. The 58 cast iron glide appears to be shorter than my TH350 with 6 inch tail. I was under the impression that the glide would interchange perfectly with the TH350, which is why I chose that trans. Disappointed to say the least. However, I found a front drive shaft for 58 / th350 conversion, online today, but I still need to call to confirm that the shaft is actually shorter and not just an updated yoke. (I found it at dr409.com). Otherwise I will purchase new yoke and get the drive shaft cut to length.