the one thing I recall was the dodge/Plymouth 360s had a cast crank that was
externally balanced so they took a special harmonic balancer and flywheel. I
also recall the AMC 360 had a side tilted distributor in the front like a
big block Chrysler engine ,but the distributor was tiled to the left side of
the engine and not the right. like Chrysler did with their big blocks.
here's some web info. this web site has some AMC stuff on it.
heads make their engines extremely competitive if not superior to other small block engines. In 1970 all three blocks grew in deck height and the strokes were increased on the 290 and 343. The 290 became the 304, and the 343 became the 360. For some reason, however, the 390 remained a 390 in 1970. It wasn't until 71 that the 390 was stroked to the 401. Like the 390, the 401's crankshaft and connecting rods are forged steel. The other change in 70 was the switch to the dog leg heads (again named after the exhaust port shape). These heads are reported to flow 50% better on the exhaust side than the rectangle port heads and are thus the best for performance. There are two reasons for the flow increase: Firstly the area of the port is larger, due to the dog leg. Secondly the shape of the port floor was changed from a concave to a convex curve. The concave floor tended to bend the exhaust flow upwards which caused turbulence when the flow was forced to go down into the exhaust manifolds. By switching to a concave floor the curvature of the flow starts in the head and proceeds much more smoothly into the exhaust manifold resulting in less turbulence and better flow. As before there were two versions, a small valve one for the 304 and a large valve one for the 360/390/401. Again, like the 290, unless you have an extremely radical 304, you're probably best to stick with the small valve head on the 304. The late model 304 head is a good option for the early 290's but there are a few other things to consider, which are discussed later.
I will tell you though the ability for parts for a 360 Chrysler engine is a
bit higher. and they are cheap to find in lots of junk yards....