I have a 79 F150 4x4 with a 351 & c-6. bad news, motor's on its last leg. Question: what motors will make an easy replacement swap? I believe the 400M is the same bolt pattern and possibly the 460 too? I think I prefer the 400 over the 351. please tell me what you know about anything here. good or bad, everything helps. Thanks--Nick

 

The 400 is the same on the outside as the 351, so you could drop one right in. I believe you can build your engine back as a 400.

John
jowilker

66 F100s
In the still cool hours of the night, you can hear chevys rusting away.

 

>I have a 79 F150 4x4
>with a 351 & c-6.
> bad news, motor's on
>its last leg. Question:
>what motors will make an
>easy replacement swap? I
>believe the 400M is the
>same bolt pattern and possibly
>the 460 too? I
>think I prefer the 400
>over the 351. please
>tell me what you know
>about anything here. good or
>bad, everything helps. Thanks--Nick
>


Johns right on with his post, I would like to add some thoughts. I am restoring a 79 f150 basically fron the frame up. The one HARD lesson you learn as you work on the truck, is where do you want to be with it when your finished. I started with just a idea of a new seat and paint inside and out. As I worked on it, I wanted clean parts, no rust on, and on. Now I have a truck that is 70 % diamantled and am going to end up with a show quality truck (and show $$$ invested) that I did not really intend for it to be. Enough whining, ha, just a little insight for others I hope working on these trucks. I am getting my buddy to rebuilt my 351m, at his machine shop, converting to 400. When you think of engine work, remember gas mileage expected, (everyone has different annual milage, and pump prices will not be going down on the long run) think of what your truck will be doing, ( heavy tow, offroad, daily driver,) that plays in when you get the cubic inch/h.p. needs you have. I will have $1500.00 in my engine/ parts and labor. Changing to 4 barrel carb/ intake, r/v cam, blueprinted, ported/ polished, all new bearings/seals, pumps, h/v oil pump. Keep in mind, tricks and cu./ hp. =$$$$, soory for the long post, good luck on your truck engine,

 

Yep. the the 351 is actually a "351m400" same motor with different stroke and tech crap. I have a 78 f250 4x4 that has the 351. As I write this I have a 460 (salvaged from a 77 LTD) awaiting transplant. My philosophy is why rebuild a 351 when you can have a 460! (No replacement for DISPLACEMENT) The 460 tuned properly will yeild about 10-12mpg. The 351 isn't any better. But when you need torque the 460 has it.

 

Dwayne is right.
460's better than the 351m/400
if you wanna drop in a 400 be careful cause they have head crack problems.....the valves run too close together.

 

Will the 429/460 bolt in though, I don't have the time now to do all the tranny swapping, motormounts, etc. thanks--Nick

 

I have the same question. My brother is looking at a 68 F-350. It has an auto on it, I presume it would be a C6. The current owner said it has a 400 in it. Would a 460 bolt up to this? What mods would be required?

Thanks

 

If the 460 was attached to a c6 and you have a c6 I don't think any flex plate changes are necesary. I haven't yanked my 351 yet so I'm hoping to use the 351 motor mounts on the 460 but as yet not sure if they will work. Additionally, I viewed a stock truck with a 460 to compare and it's an identical set-up as the 351 as far as a/c,p/s brackets. Incidently, the 460 I got was from flexplate to fan and air cleaner to oil pan. That makes for a much easier conversion. To piece together everything you would need would cost a bundle. I'm going to transfer the 351 brackets to the 460 and rearrange the p/s, a/c, to duplicate the 351 set up. Hope this helps and good luck. PS. To rebuild my Knocking 351 would have cost more than the 500.00 I paid for a complete running 460. Make sure you shop for a good one!

 

I just rebuilt my 351M up to the 400. I have a buddy with a 460 with 4bbl and headers in his 79 and I find I have no problem keepin up with his truck. I do think I have a little more low end torque in my rebuild without the extra weight of 460. Just my opinion. I did put a stronger cam and the Ohio flat top pistons and a steel crank into the rebuild and shaved .010 off the heads and bored it .020 on the block with headers and 4bbl carb and C6 tranny. Hope this helps.

BJ 1977 F150 4x4 Custom Flairside 400/C6

 

Extra weight of the 460? I'm pretty sure both engines are of the medium (light duty) engine design. The 460 has always been billed as a light weight/light duty truck engine. It's not in the same class as 360/390/etc.. I don't doubt your fresh 400 will keep up with it. But I'm thinking his 460 should have more torque. Of course, I could be completely wrong but most of the manuals I've read seperate it from the major Ford Big blocks. I think the 351m is a great motor but if your going to rebuild something the 460 has alot more potential. What do you think?

 

I am not being sarcastic here, these are real questions from someone who doesn't know.

I didn't know the 460 is considered a light duty truck engine. It always seems to be reffered to on the FTE site as being the biggest best torque producing gas motor Ford makes. I've seen many posts taling about swapping everything (even 360, 390) to the big block 460 for more power. So I am confused in the above reply says the 460 really isn't in the same class as the big block 360, 390?? Made it sound like the 460 is light duty truck engine and the 390 is a heavy duty truck engine.

Please someone untangle my brain.

 

liltoot, My post was kind of a question as well. I have read in manuals that it is for light truck apps and when looking at "Building Ford Big blocks" manuals - there isn't any mention of the 460. So I posted that to get some feedback from the folks that may know. It's certainly not a small block.

 

You are correct in that the 460 has more potential. But when I decided on what to put in my 77 F150 I wanted to build something that not everyone else had around here. The 351M is so overlooked for hot rodding and most of my buddies are running the 460. I wanted less motor weight and just as much horse under the hood so I decided to take my original engine and use the tech article from this list and give it a try, I hadnt worked on an ole Ford truck in years. I have been very impressed with the results, a very healthy 400 that can still run on regular gas and gets 10 to 11 mpg's.

BJ 1977 F150 Custom Flairside 4x4
400/C6