351 changes 1973 to present - motor mounts/manifolds?

[erikgreen]

I have a Ford 302 from 1973 that I'm thinking of replacing with a modern 351. I'm comfortable with my boat being able to handle the HP boost, although I am going to reinforce the motor mounts and possibly the transom. The sterndrive will likely go, too.

But if I buy a new/updated Ford marine 351, will it even come close to matching the old 302/351 motor mounts? (The 302 and 351 of that vintage were very similar I understand... you could even use 351 heads on the 302 with a different crank/cam).

I'm guessing also that the old->new manifolds are very different?

Can anyone who's done a similar replacement enlighten me on this?


Erik

 

[Silvertip]

Re: 351 changes 1973 to present - motor mounts/manifolds?

If my memory serves me, there were three iterations of the 351. A 351C (Cleveland), 351W (Windsor) and a 351M (Michigan). I owned a 1978 Century that had a 351/OMC in it and I believe that engine was a 351M. As the saying goes "the life of a Ford parts counter man is not to be envied" and I can attest to that. Interchangeability of Ford parts in those years was a nightmare to sort out. Do your research carefully.

 

[Fishermark]

Re: 351 changes 1973 to present - motor mounts/manifolds?

But if I buy a new/updated Ford marine 351

I think that's going to be your main problem. I don't believe Ford makes marine engines any longer. And hasn't for quite some time.

 

[erikgreen]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Okay, then let me be more specific. I'm looking at the following engine, which I think is an OEM on the ford design:

http://www.ebasicpower.com/engines/base/351.htm

I suppose then the problem is that I have to find someone who's installed one of these specific engines, instead of just a generic "ford 351"?

 

[Fishermark]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Sorry. :$ My mistake. I guess you can still buy Ford marine engines. Having said that, while I have worked on a few, I couldn't tell you specifics as to what matches what. You might ask where you are purchasing the engine.

 

[Silvertip]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Your best bet would be to find a Ford car enthusiasts web site or simple Google something like "Ford 351 History" or "Ford 351 interchange" etc. Any local auto salvage yard has an interchange book and can tell you in a heartbeat what interchanges with what. The fact that the link you posted indicates this is a 5.8L small block says its based on the 302 so I'm guessing it would interchange, but you didn't hear that from me.

 

[Silvertip]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Just one more thing. I forgot to add that just because the block is the same, does not mean all the accessory items will bolt on. I would be particularly concerned about the exhaust side of the engine (manifolds/risers, etc.).

 

[Laddies]

Re: 351 changes 1973 to present - motor mounts/manifolds?

First choise would be call epower and ask, next would be ck the gaskets for interchangeablity, my book says if if is a windsor the gaskets are the same as a 302 so the manifolds and parts should work

 

[aerwin]

Re: 351 changes 1973 to present - motor mounts/manifolds?

the 351(M) is a a 351 that was factory modified to a 400, same principal as the 383 stroker by G.M. I have a 80 truck that has this engine in it. ford needed something to compete with g.m. in a small block. very finicky to keep running right , timing is always an issue

 

[Reel Poor]

Re: 351 changes 1973 to present - motor mounts/manifolds?

The 351 your looking at will fit. You will have drive belt, accessory bracket, Y-pipe, throttle cable bracket, and maybe some clearance issues. The 351 is a little bit taller and wider.

 

[erikgreen]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Reel - thanks for the input.

As long as I'm not doing completely new motor mounts with the associated drive alignment issues I'm relatively happy. I have to build a new doghouse anyway, and I'm ok with enlarging the deck cutout around the motor.

I'll probably call ebasicpower and go over specifics with them before I purchase too, just to be sure on fit and mounting.

Erik

 

[andy1canada]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Hey Erikgreen!

Sounds like you are going through the exact same thing I just went through.

I just bought an older 19' boat with a 1980 302'/Mercrusier setup in it. It has a just serviced pre-Alpha leg on it but the raw-water cooled 302' is toast. I too was thinking of dropping a 351' in her.

My automotive mechanic pointed out to me (he's a diehard Ford man) that the 351' is a fair bit wider than the 302'. He told me about the 7 - 11 rule with these two motors. The 302' is 7-inches across the top of the intake while the 351' is 11-inches. I've also learned that the heads are interchangable (along with some other parts)
between the two. They say the ultimate deal is to find yourself a set of Boss 302/heads and throw those on and whamo - you got yourself a Boss/351.

Me, I'm pullin' the whole works from my boat and sellin' it off for parts then dropping a new 350/Mercruiser package in her. I figure what the hell, I've been buying used junk all my life and it's time I owned a worry free boat.

Now all I need to do is decide whether to spend the extra bucks on an MPI system; why am I vaccilating you ask?

Because I don't know what sort of track-record these marine MPI systems have so far and I don't know how long they've been in use...

Hope this helps.
Cheers,

Terry Anderson
Victoria,BC. Canada

 

[Bondo]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Ayuh,..... The 351W should just Drop right In.....

If my memory serves me, there were three iterations of the 351. A 351C (Cleveland), 351W (Windsor) and a 351M (Michigan).

What I know about the Fords is,......

The 351Windsor will interchange with the 302,+ the 300cid,I-6.......
These are Ford's idea of a Small Block motor......(Same Bellhousing Bolt Pattern)

The 351Cleveland is a Big Block motor,......
And, the 351Modified, is Actually a 400cid. BIg Block as Well.........

 

[jdooner]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Heads up..the 400 and the 351m are classified as small blocks, as are the 302 and 351W and the 351C. The 302 and the 351W don't have the same bellhousing configuration as the others. If I remember right the 351W heads will fit the 302 but require a special head gasket. The Cleveland heads will fit the Windsor but modifications are required to the head and block. due to water jacket passages and valve to cyinder wall interference. The call them "Clevors". Honest!
jd

 

[Bondo]

Re: 351 changes 1973 to present - motor mounts/manifolds?

You Maybe Right jdooner,......

Unlike Chevies,.....
I was getting to the Fact that Only the 302,+ 351W share the Same bellhousing Bolt Pattern......

The sterndrive will likely go, too.

IF that's so,........

You're NUTS not to go with a Chevy Repower........
'cause,...... IF this is a Mercruiser,...... You Won't be able to bolt-up a Ford to a Newer Mercruiser.......
Period........

Fords will bolt-up to ONLY the Old Mod.1 drives.......
There's Too Many differences to adapt Any of the Newer Mercruisers to a Ford......

You Didn't Say,... So, I'm just Guessing here........

 

[erikgreen]

Re: 351 changes 1973 to present - motor mounts/manifolds?


IF that's so,........

You're NUTS not to go with a Chevy Repower........
'cause,...... IF this is a Mercruiser,...... You Won't be able to bolt-up a Ford to a Newer Mercruiser.......
Period........

Fords will bolt-up to ONLY the Old Mod.1 drives.......
There's Too Many differences to adapt Any of the Newer Mercruisers to a Ford......

You Didn't Say,... So, I'm just Guessing here........

It currently has a pre-alpha Mercruiser 888 on it. Is there a comparable cost option for a chevy? I can get the eBasicpower 351 for about $3400, or a reman for much less (I'd buy new heads if it didn't come with it). I have a small machine shop available and I can do some basic mods to make the accessories fit without too much trouble.

If I recall, a reman mercruiser 350 Mag MPI package costs about $5000 with an Alpha I?

I've also been looking at a 350 repower package that comes with everything but the Y pipe for $3500, but that would mean I'd have to replace the sterndrive before I go on the water.

If I understand you correctly, the only drive that I'd be able to attach to the 351 when I get around to replacing the old pre-alpha would be another pre-alpha? That sucks.

If I had a choice I'd put in a 350 MPI and a Bravo 3, but that's $$$.

Erik

 

[Bondo]

Re: 351 changes 1973 to present - motor mounts/manifolds?

If I understand you correctly, the only drive that I'd be able to attach to the 351 when I get around to replacing the old pre-alpha would be another pre-alpha? That sucks.

That's Exactly What I'm Saying..............

The Pre-Alphas have the Rear Motor Mounts spaced at 15".........

All the Alphas,+ Bravos are spaced at 9",.........
And,.... I Don't Think there are Any Flywheel Covers(aka. the Rear Motor Mounts) available with the Ford Bellhousing Bolt Pattern,....
That'll fit the 9' Spacing......

 

[Haut Medoc]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Are you referring to the drive itself, or the entire deal?
IE, transom shield, gimal ring, bell housing?....
If you are talking about the drive unit itself, an Alpha 1 gen1 will bolt right on ......
That is if you are keeping the transom shield & related parts.....
It sounds to me like you just want to change the engine & drive......
Not the transom shield.......
Or am I wrong?........JK

 

[erikgreen]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Right Haut, I'm not planning on changing the whole drive since I don't want to rework the transom at this point, and my understanding is that as long as I keep the HP under 300 or so the Alpha 1 drive (actually an aftermarket drive) would be fine.

So, if I purchased a ford engine that matches the current motor mounts (351 from eBP) I could use an Alpha1 gen1 sterndrive? That matches the info I got from SEI (Sterndrive Engineering) about their aftermarket stern drives, which have a alpha I gen I compatible variant.

If I had to replace both the drive and motor because I couldn't use anything except the old pre-alpha drive I have with the ford 351, then I'd go with a chevy. If I can instead use an SEI or gen I alpha I drive with the 351, then I'll go that route, and if I keep the boat long enough (20+ years?) I might replace the whole rig with something newer.

Erik

 

[Haut Medoc]

Re: 351 changes 1973 to present - motor mounts/manifolds?

Yessir......
That is exactly my plan for next year.....
I was lucky enough to pick up a brand new 351 with all the tin for $1500.00 off ebay......8)If you are gonna do the work yourself you have chosen the cheapest route....
One thing you will need to do is go to center rise manifolds/risers.......
The 351 will not match up to the 'Y' with the log style manifolds........