Bill was kind enough to change the title of this thread for me (I understand why people would be leery of something titled “For Uncle Bob” ). As the thread has kind of taken off I decided to just keep it going with the build.


I spent the last couple of days getting the mock-up motor and transmission back in the truck. It was pretty straight forward and the engine sat right back down on the mounts.



Just like I figured I had to lose a bit of the original floor to get the rear of the transmission up where it needed to be. The size of the 518 Overdrive section actually took up less room than I was afraid it was going to.



The real work was modifying the crossmember (actually it was the crawling under the truck for all the times to measure, get tools, weld etc).

I knew going in to this that the 518 torqueflight had a different mount location and hung down further than the 727 I originally set it up with. On the original mock-up I ended up with a fairly simple crossmember using a re-drilled Chevrolet transmission mount. The Chevy mount gave me the right height and is a lot easier to build around than the common round mounts that Chrysler is fond of.





As it turns out the spacing bolts for the mount on the 518 is almost identical to original bolt location on the Chevy mount. I ended up opening the original holes about 1/16” and it bolted right up. I decided to add a bracket to the front of the crossmember I had already built to get it the correct height and pretty much called it good for now.






The crossmember will still need some more work down the road. When I box the frame I will have to shorten the crossmember, redo the ends and build new mounting brackets on the inside of the frame rails but for now it mounts the transmission where it needs to be so I can build the floor and firewall, and get the drive shaft angle close when I change the rear end.