F-2 Speedy

iTrader: (6)

The gen 6 has an aluminum timing chain cover with the timing tab cast into it, with an O-ring seal to the block

mike tkach

iTrader: (3)

and it has 6 bolts instead of 10.

F-2 Speedy

iTrader: (6)

Was the gen 5 the first one piece rear main seal or six, trying to recharge the memory bank,

snapmorgan

iTrader: (2)

gen 5 was first for the 1 pc seal

airjunky

iTrader: (2)

If this guy produced a fresh 420 gen4 for a repower of a 1979 boat in the year 2012 guy may have some good connections. I wouldnt mind sitting down and having a beer with him. if it was pulled out of his cousins camaro, never mind.

SB

iTrader: (1)

GM Performance Parts (GMPP) has a 454HO rated at 425hp. Lots of people by GM crate motors and drop them in boats. Psst: not saying if that's right ot wrong. Just making a simple statement.

Just a through thrown out of my head into the internet land. LOL.

sutphen 30

well it is a good base to start w/ and for the few I saw,,the piston clearances were loose so thats why they survived.bearing clearances were a touch tighter than most of us use but a bigger cooler kept temps under control.

KAAMA

iTrader: (1)

I only read a few posts within this thread,---I don't know what all was said previous to my post, but I hope that this might help a little in some way.

Anyway, If I remember correctly, the Merc 365hp 454cid engine is a 4-bolt main block with all Forged rotating assembly. They only come with the factory stamped steel rocker arms, sheet metal valve covers, Rochester Quadra-jet carb, and hyd flat tappet cam/lifters, but they DO have the GM rectangle port heads. The forged rotating assembly makes it a strong base engine for adding more hi-perf parts to it and kick up more HP.