1994 F-250 351 - recommendations

jones01m

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May 23, 2011
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Hello Team iBoats,

It has been some time since I have been on the forum, however I am back on my rebuild and will take it over the finish line in this last push. My 302 (888) short block is shot and cannot be rebuilt due to heavily pitted cylinder bores that are .040 over already.

Got a ford F-250 351w roller long block out of junk yard and building up, which has low miles according to VIN. I think I have most items figured out for fit up adaptations but looking for some basic guidance on intake manifold/carb selection (and possibly cam) to get her moving. Of course the original auto engine had EFI, which I cannot use for my marine application.

Would not be opposed to installing EFI but has been hard to locate doner boat for this application and have been looking for last 3 months. The carb route will work just fine for me.

I also realize this post could work in the OMC and Volvo forums, but thought I would start here.

Thanks a bunch. I am glad to be back on the boat obsession!
 

Bondo

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I think I have most items figured out for fit up adaptations but looking for some basic guidance on intake manifold/carb selection (and possibly cam) to get her moving.

Ayuh,..... So dress it up with the accessories off yer ole motor,....

The truck cam will work just fine, no reason to swap it out,.....
 

Rick Stephens

Admiral
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Aug 13, 2013
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6,118
I had a 1 ton flatbed with a 351 in it. Ran it with an Edelbrock Performa intake and an application appropriate Holley carb. Had to do a lot of gyrations to pass smog every year was the only downside. A great choice for carberation on your boat would be the Edelbrock 1409 on the Performer non-EGR intake. Easy to tune. Like Bondo said, the stock pickup cam is fine.

One experience I had with the 351, I tried a high volume oil pump in mine when I built it and I was constantly shattering the roll pin that held the distributor drive gear to the disty shaft. My temporary fix was a chunk of 7018 welding rod instead of a roll pin. Reality is, no need for a high volume pump. Went back to standard and never had issues again.

The Windsor's a good motor.

Rick
 

harleyman1975

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May 12, 2003
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959
So are we saying a 302 and 351 share the same intake? I seem to remember that the 351 is a little taller or wider (can't remember).
 

jones01m

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May 23, 2011
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The biggist difference between 302 and 351w is the .5" additional deck height, which allows for more cubes. Head bolts on 302 are 7/16 versus 1/2 for 351. Heads can be shared between the two engines but one must concern themselves with bolt and hole sizing. The 888 came with 351 heads, which are pretty nice old school 60.4cc chambers. If for some reason I wanted to put these 351 heads on my new 351, I would have to drill them out to 1/2", because they are drilled 7/16.

Since heads are basically identical (except bolt holes) the extra 1/2 deck height will not allow for an interchangeable intake. 351w intake is unique. So, I will need new intake and will be following up on the recommendations from Rick. I think my two barrel carb for 302 may be a bit constricting.

The one issue I may face is the flywheel. I must keep the same flywheel cover to mount to inner transom plate. There where different size 351 flywheels throughout the years. I know the mercruiser 233 was a 351 and shared same cover as 888, so there must be a flywheel that I can make work if it does not already bolt right up. We will see when I get everything uncovered.
 

Bondo

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Ayuh,.... If by chance the truck ya got the 351 from was a standard transmission, the flywheel on it will work,.....
 

jones01m

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May 23, 2011
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Bondo, thank you for the tip. This will help a lot in the salvage yard search if needed.
 

jones01m

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May 23, 2011
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Folks, I got a new marine distributor (NOS), which I am vey happy with @ 50 bucks. I already had the electronic pertronics module. Now about that drive gear... I have read much about needing to replace with hardened gear for the hard roller cam. I won't tell you why the gear from the 5.8 is no longer any good. It also looks like the position of the pin holes are different by about .050".

Does anyone have experience with purchasing a hardened gear that will maet right up to my NOS distributor without paying 60 bucks?
 

jones01m

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jones01m

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The two above pictures are of the same engine. I have incorporated the changes suggested in this post that resulted in the carbureted version.
 

Bondo

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Now about that drive gear... I have read much about needing to replace with hardened gear for the hard roller cam. I won't tell you why the gear from the 5.8 is no longer any good. It also looks like the position of the pin holes are different by about .050".

Ayuh,..... Bein' a Ford, that's a Ford question for a Hot Rod Ford forum for the Best answers,....

I don't do Fords,....
Heard 'bout that problem with some Chevys, but also don't believe Everything I read in internet forums,....

I did abuncha readin' awhile back 'bout it, 'n it comes down to a well balanced valve train, cam selection,.....
Switchin' distributor gear materials just moves any wear from mismatched components somewhere else,....
 
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