Who makes powerglide crossmembers for our cars? Is it something I am going to have to do custom?

 

Powerglide is almost identical to TH350 for size. It was always common to yank out your old powerglide and install the new TH350 tranny back in the 60's.

The TH350 uses an adaptor plate to attach to a 700R4 crossmember. A similar setup should work for a powerglide.

I fabricated my own custom crossmember because I lowered and moved my engine back a bit.

 

http://www.spohn.net/product.cfm?productid=1319

 

i found a sphone crossmember on ebay never installed, nice part, has a driveshaft loop integrated on it as well.