Flywheel question

very clearly a ‘72 up engine, just in all these years I’ve never messed with switching flywheels around. I knew there were differences, just usually whatever I was doing projectwise kept the same flywheel. I found this page with a ton of information built around something Eddie Stakes wrote. I’m a bit skeptical about a little of the info because of the 304 pictures with counterweights and Eddie Stakes says 304 didn’t have counterweights. http://rebsamcandjeep.proboards.com/thread/585/amc-290-401-flywheels-flexplates?page=1 Build date on my 360 seems to be August 17 1971 making it a real early ‘72. I was told when I got it that it came from a Matador wagon. The only time I’ve done an automatic to sick swap was about 30 years ago in a ‘71 Gremlin where the crap six cylinder automatic died and I had stick parts readily available. Pretty lucky looking back considering it was a ‘71 six cylinder, but back then you could scare up parts.

Eddie Stakes says 304 did not have a counterweight. A very detailed page I found says 304 and 360 shared a flywheel with counterweight from 72 to 78. I had a 72 Gremlin 304 that was incredibly smooth that I pulled for a 401. When I took the flywheel off the 304 it had a counterweight, but it also had a bolt welded on it. I’m guessing hillbilly balancing? Main point is I’m wondering who is right and does 72 to 78 304 and 360 use the same flywheel (outside of the individual engine balancing)?

the flywheel crankshaft recess measurement on a pre 1972 engine is 4.50", a 72 on up crankshaft recess flange diameter is 4.65, so the matting surfaces are different diameters, in theory you could bolt a late flywheel to an early crank but it won't fit tightly and you are relying on the bolts alone to keep it attached. not good. I don't think its possible to bolt up a pre 72 flywheel to the larger diameter crankshaft flange. so what year is your 360? is it a stepped or flat flange on the end of the crank?

The guy with the flywheel is interested in trading possibly for my flywheel. I have suspicion it is a 290 or 343 flywheel. Engine has not been rebuilt. I know or at least I remember now that ‘72 up centers on the step , but can you get away with the older flywheel like I have currently on there that stops short of the step and centers on the crank. 

So that is the number of the flywheel you currently have? I might be interested in it if will work for one of my engines.