The transmission and engine are mounted about 3 inches back from the Firebird original location. I tried four sets of headers before finding a set of shorty headers that fit the angle plug heads. I used the later model metal engine mounts and wekded them to the crossnember. I used 1957 Chevy motor mounts mounted them to the motor and it fits perfectly.
The transmission cross member was a left over from a modified Mustang I did a few years ago. I bolted the cross member to the frame and welded a plate to cross member to use the original 700r4 mount.