454 longblock brand new.

opie272 · Aug 16, 2004

I have to buy a "new" engine but am confused as to the specs I was given.
Can anyone shed some light on this.
GEN V 454 FI 385 h.p. rectangular heads.
Did mercruiser make a GEV V fuel injected 385 hp engine?
I was thinking of running a carburetor. Will it work with the FI heads? Would it be better with the FI heads because of flow, or about the same as non-FI heads.
I hear a lot of talk about oval vs rect. port heads but nothing about FI heads.
Are rect heads different than FI rect heads?
I will be buying 2 so does that make a difference?

I'm so confused!!!!! :confused1 :confused1

Brad Perry · Aug 16, 2004

"Are rect heads different than FI rect heads?"

- I've never heard of a difference. I thought they are one in the same. As to whether merc ever sold a gen V 385, don't know.

cfm · Aug 17, 2004

Yeh, the 454 Magnum MPI was 385hp.

It has rectangular port heads, steel crank - but - the Gen V version has the hydraulic flat tappet cam. The roller cams came in the Gen IV's.

This was the same set up that the 502 415hp MPI's had.

Note: Gen 5 and 6 blocks cannot accept OEM GEN IV heads. Aftermarket heads usually wii fit all versions.

opie272 · Aug 17, 2004

This is supposed to be a brand new long block, but when I called the guy he said it was a GEN V 385 hp. FI rect port head engine.
Looking at mercruiserparts.com the only match I can find is the 7.4 MPI GEN V.
BUT....the salesman said it had roller lifters.....So is this a GEN V or GEN VI.
Or does this guy not know what he has?

cfm · Aug 17, 2004

That's actually better.

The GEN V and VI use the same head set-up. All things interchange between the two but the Gen VI has the roller cam set-up.

I'd take the roller cam motor.

Intakes will bolt on - no matter what the year. Just as long as it is made for rect port heads.

Brad Perry · Aug 17, 2004

Ask him if it has a cast aluminum timing cover or a stamped steel one.

Sounds like it is probably a Gen VI. I'd be a little suprised if many new gen V long blocks were still readily availiable.

opie272 · Aug 17, 2004

I guess what I am trying to avoid is buying a pair of 310 hp. 7.4 motors when I have a pair of 330 hp now.

For some reason I DO NOT want to go down in h.p.

I want to go up in h.p.

Does that make sense?
If I'm going to spend the $$$... I can get some rebuilt 420 hp engines for about the same price....but....the idea of brand new longblocks and less chance of problems with a rebuilder makes me lean to the "new" motor.
:confused1

cfm · Aug 17, 2004

You can get new GM marine 502 longblocks for around $5200.

See www.1800runsnew.com If you call them - 1-800-Runs-New let'm know Scott from CFM-Tech sent ya.

They have good deals on new GM 454 marine engines too.

cfm · Aug 17, 2004

I just checked - new GM marine 502 long blocks for $5200.

DonMan · Aug 18, 2004

Gen V and VI: 1 piece rear main seal, cast aluminum timing chain cover. 310 hp 454 has large-oval port heads. 385 hp 454 has rectangle port heads. Gen VI 454`s have roller cam..385 hp and 310 hp.
Avoid it if 310 hp.
385 hp "Mag" engine is good choice.

Brad Perry · Aug 18, 2004

So basically, if it is the factory combination with rec port heads, then it has the good forged parts and a heathier cam....even though the late model vortech heads are good too, the combo will miss many other things. Gen VI just puts icing on the cake with a roller cam. READ rec port, mucho more hp than you have now, ANY factory Oval port motor = same low hp with possibly better heads.

That new GM marine 502 is a hard value to beat! The price hasn't changed in at least 5 years!

454 longblock brand new.

opie272

Brad Perry

cfm

opie272

cfm

Brad Perry

opie272

cfm

cfm

DonMan

Brad Perry

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