Finally found a non lock up 518 to go in my Challenger. Came out of a 91 church van. It is at a shop now being torn down and inspected for hard part damage.

Next step will be all the clearance work to the tail of the case to fit in the E-body.

When I get to the point of having it rebuilt. What updates do these transmissions need to live in a street car. Currently it will go behind a warmed over 360, probably next year a mild stroker built for low rpm torque.

It is basically a 727 with an overdrive unit mounted in the tail-shaft. Pretty stout unit for what you are doing.

Early A518's had a lot of overdrive unit failures due to not enough lube/cooling oil flow through the intermediate shaft. O/D unit would overheat, cook the fluid, then cook the trans. While the shafts holes can be drilled to improve flow, it's a drill bit-eater, due to the shafts being induction hardened. Most shops will simply install the upgraded intermediate shaft with larger lube holes.

I will store that bit of info under 518 upgrades. I recently scored a JW Ultrabell for a BB and while my racer is a BB, I was going to hang it on the front of the race built 727. After talking to a few local racers, I realize that it is overkill for my situation in the race car, but I could use it in the tow vehicle to mate a big block to a 518 and slide that into the '87 D100 when I fit it with the Dana 60-2 that will lower the final drive to 4.10 from 3.21. A lot cheaper than a Gear Vendors OD setup.

There are basically stock replacement ones with larger holes all the way up to billet units for the pumped up 1000+ H/P diesel crowd, and are priced accordingly. Sharp rebuilders, like John Kunkel, can probably tell you when they fixed the issue and what year the stock ones came with larger holes. Also, the O/D clutch drums interchange between the A518 based O/D units, with different amounts of clutch discs. In other words, there are stock drums that have higher torque capacities that may be able to be fitted into your O/D unit.