My gosh, no grass grows under your feet. You’re like the Energizer Bunny…on steroids! Very impressed with the speed of your project.
From reading your posts it seems you're taking the transmission and associated parts from the 360 and installing them on the 318. My concern with that is you may be unknowingly making a mistake, and I’d hate for you to discover it after the fact, and have to pull the engine and transmission to rectify it.
While the 318 and 360 engines are both from the same LA engine family, there are some differences. The 318 is an internally balanced engine and the 360 is externally balanced. A 318 requires neutrally balanced harmonic balancers and flywheels, whereas a 360 requires counter-weighted components. Mixing the two will cause unhealthy vibration issues. I have considerably more experience with GM and Ford engines than Chrysler, so please accept that as a disclaimer. I THINK the setup Chrysler used on the 360 is a neutrally balanced flexplate and a counter weighted torque converter. That would mean you would need a torque converter made for a 318. But, please confirm this with someone far more knowledgeable than I.
Our 1986 Tucker 1544 came with an AT545 from the factory, and Tucker installed a 12” x 24” Hayden brand fluid cooler in front of the radiator to cool the transmission fluid.
With regard to the the 3,500 RPM limitation... here’s my theory:
Tucker used/uses Vickers V20P hydraulic pumps and Vickers has a maximum recommended RPM for their pumps. It changes based on the pumps volumetric output, but 2,500 RPM is a good baseline number. Tucker under drives the hydraulic pump with the geometry of the V-belt pulleys. IIRC, Tucker uses a drive pulley (mounted to the harmonic balancer) that’s 6” in diameter and the driven pulley (on the hydraulic pump) is 8”. Mathematically, 3,500 engine RPM would equal 2,625 pump RPM, a bit more than the maximum recommended by Vickers, but not egregiously so.