i'm getting close to engine time but not so much as i'm in a rush, just trying to think ahead.
before i make an offer, or a move

would a late 90's 454 mag mpi serial ok02xxxx be a good base ?

forged rotating assy ?

it's a distributor motor, and if it's forged, the first thing that comes to mind is might be good candidate to become a
1987 420 clone in gen6 form
or a
1995 450 clone in gen6 form.
either will be closed cooled block only w/ hardin cyclone shorty header and dry tail.

i mean pretty damn cloney, i want to buy a merc owner / operator and service manual, so i can do plugs, timing, lube, fluids and filter changes right out of the book.

building tuning jetting and the how's and why's of engines are not my area, so the real deal or a clone it's gotta be.

the hp range i'm in also puts the 496 mag ho on the table, the right one comes up, i think i'd be happy but i know less than zero about computer engines.
i only know from what i read and heard that in stock form the 496 mag ho is a reliable and strong engine package.

i'm after turn key go boating, 500-600 hours later, compression and leak down test

thanks guys

That 454 is an excellent base.

I'd make it a 525sc clone with updated cam and a bit more static compression. Good runner and reliable right there. I have always liked that motor. Common parts and the blower's come across here reasonable too.

The gen 6 454 is a great base motor depending on how much HP you are looking for but sounds it would fit your scope of needs.

i looked hard at the 525sc, it only has1 problem, 92 octane,
i'd have to take it out of the water every time i need gas,
because i don't know where to get 92 on the water around sebastian inlet fl.
my other goal of 420-450 hp is to stay inside the design limits of the b1
but thank you it's a good suggestion.
i'll move on engine right now, it's just gonna have to be the right one and i gotta know it's not some frankenstein that's ready to come apart.
i know good luck right !

I have a gen 6 454mag in the swap shop if you are interested

Yes it's a full forged engine and a good base. The 80s 420 is a good motor but go to a roller like the hp450.

I got an extra set of Merc racing valvecovers Id sell ya. Get you started cosmetically.

that's the thought, a 420 or 450 clone (in gen6 form) ,full roller, mechanical fuel pump, mechanical secondaries, TB4 ignition

You'll need Gils or better exhaust but yes they are set it and forget engines.

Most gen 6 blocks do not have a provision for a mechanical fuel pump. You can use the setup where the fuel pump mounts on the sea pump, but it is not the best option.