700R4 GM in a Swinger?

The Kiesler kit is based on a much evolved version of the 700R4. Basically a 1/2 ton truck tranny, plenty strong enough for a small block. The early 700R4's had some issues, but they were mostly fixed by 87 or so. If you rebuild a core transmission, there are plenty of beef up parts for the 700R4. In stock form, a 700R4 is probably stronger than an A500 (especially the converter).

Adapting an A518 isn't that difficult, but there is some surgery needed to the floor pan and the rear crossmember. And since the rear crossmember carries the weight of the front suspension, you can't just cut it away. Plenty of magazine articles out there. Eherenberg did at least 2 articles on this, both in HP Mopar in like 89, and again in Mopar Action in the 90's. I might be able to scan a copy next time I'm near home.