This adapter is for a G50, don't know if the G50/52 has the same bolt pattern.
KEP sells one for about 200.00 I just wanted to make my own so I could integrate trans/engine mounts.
The mounts aren't drawn in this 2D .dwg, they are on the bottom corners and are urethane just like the rear trans mount you mentioned.
This adapter is made from 5/8" 2024 T4(?) plate. I bought a piece from KEP when I bought the flywheel/clutch package.
The G50 locates with a lip on the inside edge of the adapter, the 302 locates with 2 dowel pins. The lip is formed by machining a 1/8 x 2" wide band that the trans bolts to and leaving the 5/8 thickness to form the lip.
first you cut out the large center hole that the flywheel fits in and drill the trans holes and machine the lowered band area.
Then you clamp the adapter to your block with the crankshaft bolted in.
The most important and most tedious step is to perfectly center the large center hole to the crank, + or -.005"(?). Then you center punch the two dowel pin hole locations on the adapter with a transfer punch that you put through the back of the block dowel pin holes. The transfer punch has to fit very tight in the dowel pin holes otherwise it won't be accurate.
Then drill the dowel pin holes on the adapter with an accurate drill press or mill.
It's been about 2 years since I built mine, I may have transfer punched the trans holes also. Without a 24" caliper it's the most accurate way. The hole locations in the drawing aren't that accurate because I didn't have the proper measuring tools. It's just a general plan and you mark the holes accurately using the transfer punch method.
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just realized I misread your post, oh well maybe someone needs plans for an adapter also /ubbthreads/images/graemlins/grin.gif