Im new at all this and recently I purchased a truck (1978 4by4 F150) with a 351 m , which I would like to rebuild this spring. Ive read and heard alot about oil pressure concerns in this engine and the last thing I want to do is drop money into a engine that will never produce results other than regrets. My question is should I bother with a modified, or are there another engine which is better design? I want a beefy motor, alot of torque, a small RV cam, what are all the factors to consider? This will be a huntin buggy, work horse, it will not be a "show truck". What are some thoughts, which will help me to prepare? I would how ever, like for it to be impressive when it performs.Thanks in advance

 

think about some early heads, pre 75 for the better exhaust ports. check out http://users.abilene.com/~dkelly/hotrod/newmotor2.html
this guy knows his poop. the 400 crank and pistons go right into your block too,if you're going to bore or need a fresh crank you might as well take the free 50 inches and 1/2" of stroke!i think you're on the right track w/the mild cam,i like comp cams 268H.its a runner.for what you are describing for usage the stock intake,maybe a holley 2bbl(even the stock carb can be tuned to suit) and headers,slight stall converter-you be rockin

 

I'm in the process of rebuilding my 351M into a 400. I had the same concerns about oiling until I read here, and in a book from MotorHaven, that the the primary concern is getting oil to #'s 4 and 5 mains. I am taking the suggestion to install an oil line that dumps oil directly onto 4 and 5. My engine builder has done this and installed a small plug in the #1 oil journal to increase to oil flow to the rest of the main bearings. He suggest the oil line and increasing the size of the oil journals on the crank as well as installing a baffle in the oil pan to keep oil on the bottom of the engine at high rpm's. Good luck.

Rob

 

I was talking yesterday to a machine shop, they said that even a small rv cam in a 351M would not be recommended because of this particular motor design. He said I would run into problems, what, He never said. So what would you guys recommend? Should I even build this motor or go with a different motor, then do I run into other problems with adapting to my tranny? I'm open to suggestions, no real hurry.

 

>I was talking yesterday to a machine shop, they said that
>even a small rv cam in a 351M would not be recommended
>because of this particular motor design. He said I would run
>into problems, what, He never said. So what would you guys
>recommend? Should I even build this motor or go with a
>different motor, then do I run into other problems with
>adapting to my tranny? I'm open to suggestions, no real
>hurry.

With all due respect to your machinist he doesn't have a clue what he's talking about. Maybe he's just not familiar with Ford motors because there's no reason you can't put a decent sized cam in a 351M providing you modify the rest of the valvetrain appropriately (correct springs, etc.) Having said that I honestly wouldn't rebuild a 351M as a 351M, I'd spring for the 400 crank & pistons and make it into a 400 to benefit from the increased displacement.

 

from another forum i remember seeing that up to .530 lift will not cause any problems w/stock rockers.they also have beaten the oiling question to death and back.use the search on the site so as not to get anybody more upset than they already are(kidding,kinda)http://www.network54.com/Hide/Forum/119419
two heads are better?

 

>I was talking yesterday to a machine shop, they said that
>even a small rv cam in a 351M would not be recommended
>because of this particular motor design. He said I would run
>into problems, what, He never said. So what would you guys
>recommend? Should I even build this motor or go with a
>different motor, then do I run into other problems with
>adapting to my tranny? I'm open to suggestions, no real
>hurry.


OK I have to say your machinist is not up to par on the Ford Motors.
One of the best machine shop in my area Just shook his head when I brought him my first 400 to machine. He told me I'd be better off with a Windsor or go with a 460, He said nobody builds 400's ...
Well I guess I'm a Nobody then.

Biggest Baddest 400 in my neigborhood Hands Down. Even the Chebby boys get weak in the knees when I fire ShaZam up.

 

coonhunter, To keep it simple. Find an old 400 thats in decent shape and put your money in it. Look in old Lincoln's, LTD's, even pickups. You can be building it and still have your truck running!

This motor makes good torque stock. A noticeable improvement over the 351M. "All" your stock hardware off the 351M will bolt right on the 400. Easy as can be.

Of course you could go to the 460, but it would take more foot work to find the parts and more money to buy the needed parts to make this swap.

 

Sir,
Thats a good idea,thanks. I do have a question,again I'm still learning, You said to find a decent 400 out of another vehicle to build up then replace to eliminate down time, which I have another 351m, if I took it and bored it over to a 400, then installed a 400 crank, pistons, etc.., would that be the same as what your recommending? Or would the over all cost probably be increased due to the modifications,boring, new crank, pistons,etc.? Thanks

 

thats a good idea to build one while still driving the other.the only difference between the 351m and 400 is the crank and pistons.they share the same bore size, 4".the difference in the pistons is the location of the wrist pin to compensate for the longer stroke of the crank.the connecting rods are identicle and interchangable,as are the heads,block,intake and exhaust manifolds,oil pan,cam,pushrods,timing set,front cover,water pump,brackets and accessories etc,etc...

 

[updated:LAST EDITED ON 01-Jan-03 AT 06:08 PM (EST)]>Sir,
> Thats a good idea,thanks. I do have a question,again I'm
>still learning, You said to find a decent 400 out of another
>vehicle to build up then replace to eliminate down time,
>which I have another 351m, if I took it and bored it over
>to a 400, then installed a 400 crank, pistons, etc.., would
>that be the same as what your recommending? Or would the
>over all cost probably be increased due to the
>modifications,boring, new crank, pistons,etc.? Thanks


I've seen that Auto Zone has 400's Cranks for a desent price.
Get a new crank and order some pistons and your good to go.
Have the Machine shop check your rods from the 351M and then have them press the pins in your new pistons and put it together.Your on your way to a new Motor.