Reporting back on the New ChevPro Marine HEI I installed in my boat. The reason I replaced was that the previous owner installed a new Accel HEI (Auto Version), and I was having issue getting top speed above about 36 mph and it seemed to be struggling to rev past 3800 or so.
I ordered a new (Marine Version) from AAA Marine Parts for my Chev 350, and dropped it in and all is good. Engine runs great, and my top end is about 42 or 43 mph, with engine screaming all the way from idle to past 4k.
This company has this GM designed HEI for both GM and Ford engines.
I recommend to those thinking of upgrading!