I guess you need to decide what engine you will run, as that will determine what transmissions will fit easily.
Are you sure the adapter from the 409 will fit the engine you will use? A friend of mine pulled the 409 out of a truck and used it in a car, the adapter stuff allowed the use of a larger flywheel and the starter is mounted to the adapter. Best I could tell the adapter stuff is no good without a 409 or 348 in front of it.

Look on Craigs list and at local surplus places. I have seen the transmissions sell for almost nothing and up to about 200 would be OK, many of the big surplus places ask way to much for them.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-