74 was the last year for the thick cylinder walled 360's. My brother has a 74 360 in his Challenger and it has the super thick cylinder walls.
I also have to disagree on 500hp not being achievable on a street 360 without stroking it. My brothers 360 is running around 450hp with a 30 over bore, stock stroke crank, 2.02 fully ported heads, 9.8-1 compression and a fairly high cam. It is very streetable and with a little more work could easily be a 500hp motor and still be street friendly.
I also know a guy at work running a 78 360 bored 60 over, 12:1 compression, ported heads, stock stroke crank with around 450hp and is running 11 sec qtrs in a 73 RR racecar.
My main point is that streetable HP in the 450-500 range is achievable with a stock crank 360. The 12:1 is to high for a street motor but the hp is still achievable for the street.
Joe