US Car Tool A518 Cross member
heres an overview of pix from my google archives on this trans install. No floorpan in the way so I reinforced the crossmember with 1/8" steel after trimming it. I also have pix of the 3/8 trans line, and kickdown cable setup, as well as how I modified the shifter rod for Mike and myself.
I'm no engineer, but I think flat strapping the crossmember the way I did, then building the trans mount to tie it all together, plus the floor pan welded to it all, it will be plenty strong. What's also nice is I left the outer bolt holes in the stock location, so if for some crazy reason I wanted to put a TF727 in there, an original A body crossmember will bolt in. I would just have to add a few holes in the OEM crossmember for the inner bolts.
The kickdown cable setup uses a combination of B350 ram van pieces, and a V8 dakota kickdown cable to get it to route correctly at the transmission and clear the rear trans cooler line. I used the kickdown cable attach bracket off a dakota throttle body, and cut it down and welded it to a piece of steel angle attached to the carb mounting bolts along with a throttle cable bracket. I'm not too thrilled about the throttle return spring setup I made, and may redo that differently. However in testing it moves smoothly without binding, and pulls the lever at the trans all in at WOT. An edelbrock bolt on cable attach lug for the carb is for a GM TH350 and clips nicely to the cable at the carb end
The shifter rod, I temp welded to a piece of steel angle, and welded an attach bracket for the shifter arm as a jig. Then cut the shifter rod apart, and re welded it with a bump out to clear the OD trans section. I welded it back together with the shifter arm bolted back in place. Works great in testing.