what cars trucks or vans did the good overdrive come in. i found a few 80's vans with od's for $160.
are they loc up, non lock up, will a 727 coverter fit it or are they a 518 base.
To be honest I don't think even the 518 is all that strong. I've read you shouldn't go more than 400 hp through one unless you upgrade the OD components.
I could be wrong but I think the OD section is basically the same on the a500 and a518 so you might as well go with a a500. It is smaller and would be an easier fit in an A-body. It's built on the 904 base and 904's will take 400 hp if rebuilt soundly.
727 and 518 torque converters interchange as long as you match lock-up to lock-up and non lock-up to non lock-up.
You can easily identify a lock-up trans by looking at the input shaft. The non lock up shaft is splined all the way to the end. The lock-up has about 1/2" of the front end of the input shaft turned down smooth.