C4 Transmission mount at the cross member

[RAWms]

I have the car up in the air to finalize stuff underneath and getting ready for the road.  I thought I could get an original '57 automatic transmission mount to work with the C4.  The C4 mount base is 5.5" wide at the trans mount and the original is maybe an 1" wider.   

What have others used for a rear transmission mount for this combination?  Part number?  I was told early Mustangs work also so checked my '66; Noop, if the 4-speed is the same as the automatic. 

thx in adavance, r

[fomocochoptop]

I think i remember using the Squarebird Auto Trans mount 1958-1960 thunderbird.  Drill out the holes a little for Adjustment and i got the to Work. And had to Drill out the Trans masion X-member Some. It was a couple years  ago So i could be wrong.