351M - Rebuild or Replace
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351M - Rebuild or Replace
Hi Guys,
I have a 78 F250 (2WD) with a 351M. She has 115K miles on her.
So far I have replaced the master cylinder, radiator, 2 new gas tanks and straps, wires/plugs and distributor cap (she never had a tune up in 29 years, all original wires are plugs), just installed a carb with a 2 barrel stock replacement, edlebrock air cleaner, misc vacuum hoses, pcv valve, battery and battery cables, and all of the fuses and bulbs. She is coming along nicely, starts and runs fine.
I have Hedman Headers and a new exhaust system which I have not installed yet. Want to replace the entire bed assembly first.
I am wondering if I should rebuild or replace the engine. I know it is expensive to just replace the entire engine, but I am not sure about a rebuild. A few shops around me in PA are not the nicest of guys when it comes to an older truck, most of them just laugh. I can't stand them...!
Any thoughts? Not sure if I want to dump a bunch of money into the body or the motor. She is rough to look at, other than the new rims and tires. They are worth more than the truck, yes, I am that guy.
Also, I am thinking about a new intake manifold, oil pan, oil pump, and water pump. What are some options?
Thanks,
Mike
I have a 78 F250 (2WD) with a 351M. She has 115K miles on her.
So far I have replaced the master cylinder, radiator, 2 new gas tanks and straps, wires/plugs and distributor cap (she never had a tune up in 29 years, all original wires are plugs), just installed a carb with a 2 barrel stock replacement, edlebrock air cleaner, misc vacuum hoses, pcv valve, battery and battery cables, and all of the fuses and bulbs. She is coming along nicely, starts and runs fine.
I have Hedman Headers and a new exhaust system which I have not installed yet. Want to replace the entire bed assembly first.
I am wondering if I should rebuild or replace the engine. I know it is expensive to just replace the entire engine, but I am not sure about a rebuild. A few shops around me in PA are not the nicest of guys when it comes to an older truck, most of them just laugh. I can't stand them...!
Any thoughts? Not sure if I want to dump a bunch of money into the body or the motor. She is rough to look at, other than the new rims and tires. They are worth more than the truck, yes, I am that guy.
Also, I am thinking about a new intake manifold, oil pan, oil pump, and water pump. What are some options?
Thanks,
Mike
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Joined: Sep 2006
Posts: 14,325
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From: Island Southeast Alaska
I would get a 400 long block from Napa as they are excellent quality. As good as Ford and for less money. I understand they are built in the same place. DO NOT GO WITH Autozone or any other crap auto supplier. Ya get what ya pay for.
All the external parts from the 351m will bolt right up. The only aftermarket thing I would do to the long block is put in a double gear straight up timing set. This in it's self will give ya better mileage and more pony's. It will come with all the gaskets ya need and then some. With things like the water pump, Dizzy etc. with over a 100k I would replace them also. That way everything under the hood is new. And with proper care will go over 200k.
All the external parts from the 351m will bolt right up. The only aftermarket thing I would do to the long block is put in a double gear straight up timing set. This in it's self will give ya better mileage and more pony's. It will come with all the gaskets ya need and then some. With things like the water pump, Dizzy etc. with over a 100k I would replace them also. That way everything under the hood is new. And with proper care will go over 200k.
Post Fiend
Joined: Sep 2006
Posts: 14,325
Likes: 14
From: Island Southeast Alaska
I would get a 400 long block from Napa as they are excellent quality. As good as Ford and for less money. I understand they are built in the same place. DO NOT GO WITH Autozone or any other crap auto supplier. Ya get what ya pay for.
All the external parts from the 351m will bolt right up. The only aftermarket thing I would do to the long block is put in a double gear straight up timing set. This in it's self will give ya better mileage and more pony's. It will come with all the gaskets ya need and then some. With things like the water pump, Dizzy etc. with over a 100k I would replace them also. That way everything under the hood is new. And with proper care will go over 200k.
All the external parts from the 351m will bolt right up. The only aftermarket thing I would do to the long block is put in a double gear straight up timing set. This in it's self will give ya better mileage and more pony's. It will come with all the gaskets ya need and then some. With things like the water pump, Dizzy etc. with over a 100k I would replace them also. That way everything under the hood is new. And with proper care will go over 200k.
Post Fiend
Joined: Sep 2006
Posts: 14,325
Likes: 14
From: Island Southeast Alaska
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Thanks for the suggestions. Has anyone ever heard of powerpro2000.com motors? They have a 351M for $1600. Thinking about going that route. I may want to think about a 400 as you guys seem to like that engine.
I want to replace all of the parts as I want this truck running like new. I am not confident at all in it's current state. It gets me from A to B, provided it is a short trip, but I may want to take it for a ride over 100 miles. Plus, I want it done right, not just thrown together.
As far as the bolt on engine components, I will just keep my eyes on the forum for the best of the best.
Thanks,
Mike
I want to replace all of the parts as I want this truck running like new. I am not confident at all in it's current state. It gets me from A to B, provided it is a short trip, but I may want to take it for a ride over 100 miles. Plus, I want it done right, not just thrown together.
As far as the bolt on engine components, I will just keep my eyes on the forum for the best of the best.
Thanks,
Mike
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Post Fiend
Joined: Jan 2006
Posts: 5,037
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From: Kasson, Minnesota
I also suggest going with a 400 or 460. But, since your current motor is running fine and only 115K (not too much for these old things), you may want to think about doing some body work if you want the truck to look good. Body work will probably be way more expensive than a new engine (unless you can do it all yourself). It's hard to decide when it comes to these projects. It's just a matter of whats more important to you now and in the future. Body work does take more time also. Your truck could be laid up for some time vs just throwing a motor in.
Tuned
Joined: Aug 2002
Posts: 476
Likes: 1
From: Greatest state on earth
That 351 M is not too bad on gas and has plenty of power, even with stock 2bbl is tuned properly. They dont even seem to use all that much oil isf guides are worn. If compression is fairly even across all cylinders and you dont have to dump a quart betewwn oil changes....Unless you just have to spend money or want more power at a high price.....Why? With current gas, the carb will definately need to be internally adjusted. If you have a C6 behind it, I would consider a NP 435 or late model OD tranny as a more benificial option. But thats just me. I am but a small voice in a large group.
Cargo Master
Joined: Apr 2001
Posts: 2,364
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From: Eustis FL
I also agree with the 'if it runs great why touch it' comments. If you want more power, bolt on some headers, a 4V intake and 600 cfm Edelbrock carb with some nice sounding duals. You could also go with a mild cam.
We are suggesting the 400 for this reason: The 400 is identical to the 351 on the outside, which means everything will bolt up the same. Why do 351 cubes if you can do 400 for the same price? You will use the same radiator hoses, even... Keep it running good and work on the body so you can keep driving the truck. The guys that are laughing at you in the shops won't be when they see your truck all 'finished'! they are probably chebbie guys anyway... No Ford guy would ever laugh at an old Ford truck, knowing their potential.
We are suggesting the 400 for this reason: The 400 is identical to the 351 on the outside, which means everything will bolt up the same. Why do 351 cubes if you can do 400 for the same price? You will use the same radiator hoses, even... Keep it running good and work on the body so you can keep driving the truck. The guys that are laughing at you in the shops won't be when they see your truck all 'finished'! they are probably chebbie guys anyway... No Ford guy would ever laugh at an old Ford truck, knowing their potential.
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thanks guys. I have made up my mind.
Dropping in headers, exhaust system, new bolt on components, upgrading the tranny (this is where I think the problem is anyway), new oil pan + pump, 2" or 3" lift for sure, new bed and 2 new doors, and then a two-toned paint job (eventually).
Can anyone recommend a 2 or 3 inch lift. I always see a disclaimer that a 3 inch lift won't work because the steering box is too close to the firewall. What does this mean exactly?
Mike
Dropping in headers, exhaust system, new bolt on components, upgrading the tranny (this is where I think the problem is anyway), new oil pan + pump, 2" or 3" lift for sure, new bed and 2 new doors, and then a two-toned paint job (eventually).
Can anyone recommend a 2 or 3 inch lift. I always see a disclaimer that a 3 inch lift won't work because the steering box is too close to the firewall. What does this mean exactly?
Mike