RE: .46 evolution vs .45 trainer system
I think the reason the trainer engine is heavier is because it has a rather large flywheel on it.
I've got the trainer engine (.455 ) that I took the flywheel off of, and it runs very much like my 2 .46NT's
The .46NT with a GMS/Tower .46 muffler is a nice, powerful combination, with either a 12x4 or 12.25x3.75 APC.