318 poly in 68 cuda
I've never had any problems bolting 273/318 LA motor mount brackets to a 318 Poly block. The Poly was the original A engine and made it's debut in 1955 as a 301 in the Chrysler Windsor. The 273/318/340/360s are in fact members of the LA family. They are not A engines, but there is a lot of interchangeability between the two. Enough to allow you to bolt your 318 Poly into your '68 Barracuda using 318 LA mounts. The real challenge is finding an exhaust system that will clear the steering.