Looking to find out if I need a different driveshaft. Just got the glide built and havent done any measuring yet.

The drive shaft is common between a powerglide and a TH350. A TH400 requires a different length drive shaft.

You will also need a trans support for a TH350/Powerglide. The TH400 trans support is different.

I have a 350 crossmember, yoke is different too i know, what about the pinion yoke, I shouldnt have to change it should I?

Pinion is fine. Same design. Ya, yoke too. If you pick up a drive shaft for a TH350/powerglide, you'll be fine. Both trans use the same output shaft.

I'm only going from experience here. I had a powerglide, it failed, bolted a TH350 directly in with no mods, ran fine.

Went to a TH400, had to replace driveshaft (new yoke and length) and new crossmember.

A few other things. The TH400 (most of them) use and electronic kick down for passing gear. The TH350 uses a cable. I can't remember what the powerglide used, but I think it was a similar cable setup.

I also seem to remember a vacuum line running down to the TH350/powerglide. I don't remember much about it, other than it was there.

Its a drag car dont care much about the kick down and all that. thanks!