I am doing a similar project but I am going to use a Jaguar front subframe.

With a little trimming a Mk 2, 3 or XJS front subframe will slide right under the frame giving Large vented disks, PS, and chevy bolt pattern.

Just cut the front legs that stick out, create a flat area for the frame and weld her in.

DO NOT USE ONE FROM AN 86 ON CAR AS THEY ARE DIFFERENT.