The 85 Frame does have holes for the TH350 & TH2004R Crossmembers.
Sounds like you have a TH2004R Crossmember, mounts almost straight across.
A Crossmember from a 78-88 V8 G-Body that came with a TH200/200C or TH350/350C will work, mounts at an angle.
The V6 Crossmembers are slightly different, had an offset mount but, will work with correct Trans mount.
Some Info/Pics here >> • View topic - Serious Crossmember Problem