Just an FYI but the later LA318-340-360 also bolts right in, no problem, in case you can find one cheap or whatever.

Just have to use 2 left side front motor mounts. As I recall for the LA's in place of Poly I had to use the left side front motor mount on right side of block, but mounted it with the 'U' shape on the front side of engine block ears or mounting tabs. The right front motor mount would normally mount behind the tabs.

There was something about the internal balanced engine's flywheel compared to external balanced flywheel but I never had any problem with it. Think I used the Poly flywheel on the LA 318 and LA 360? There was something about drilling the flywheel according to a template for balancing, can't remember that part clearly. Think it's in the archives here somewhere? I'm sure someone else here has the needed info.