Poly to LA block swap questions

Hi... I have a dodge truck (I know, I know... not an A-body.... <WINCE>) that has a poly 318 in it. Are these engines known to be weak near the top center water ports on the block at the head mating surface ? Mine is cracked on both sides of the block. This leads to the question about swapping motors. I found online (at the polyspherical association) that the poly blocks have the same mountings, bell housing pattern, and flywheel pattern as the LA engines. Is this true ? I'm looking to mate either a newer 318, or preferrably a 360 motor inplace of the old broken poly. I was planning to rebuild the poly as it is very tired, but the cracks dampened my hopes. Since it is a dump truck, I'd also benefit from the power of the 360. Thanks for any advice you might have for me. I'm looking forward to getting the old girl on the road !

Ryan in NY