I have a 351M setting in my garage that I pulled out of a 79 Bronco. I have heard that a 351W is a better motor for a Street Rod pickup. I found a 351W in a junkyard today and would like to know what's the deal about a 351W?

 

if your looking for information on a 351W you should check the windsor forum...

I'd keep the midland, stroke it to 400 and get some of TMI's 9.5:1 pistons..

 

I'd probably use the W. There are plenty of performance parts available for the W, stroker kits too.

 

the W is a bellybutton engine, everybody has one. the urban legend that there are more parts available for the W should've died 10 years ago. thanks to Tim Meyer, interchangeability between the Cleveland, recent crop of heads available, and even a manifold from CHI there is no shortage of parts to hinder a first class M/400 build. you can even use a steel stroker crank for a W to get rid of the boat anchor crank.

i keep reading posts saying that the "M/400 is a low rpm engine...", the engine doesn't know what it is until you build it as such. if you want a 2350 rpm stump puller, build it. if you want a 7500 rpm hemi killer, build it. $ky's the limit

 

I have a 351M in my truck and it runs like a dream. Personally I'd stick with the 351M and I can sum up why in 4 points.

1st. Easy To Stroke!
Like father/son suggested I would stroke it out to 400 c.i. which is much eaiser than most realize. All you need is a crankshaft and pistons for a 400, which are all parts you would have to replace anyway. Once you have those parts just swap them out and TA! DA! you have a 400. If you bore it .30 or .40 over, which you would do in a rebuild anyway, it comes out to be about 408 c.i. Unfortunatly Ford made this motors with thin wall casting which means that it cannot be bored much more than .40 over, but don't let that scare you away.

2nd. More Torque!
The 400's stroke is longer than that of both the 429 and the 460 (4.0" for the 400 VS. 3.59" for the 429 and 3.85" for the 460) which means more torque at lower RPM, which is exactly what you need in a heavy truck. Just to give you an idea if you compare maximum torque figures for 1972 (SAE net measurements) it shows even more dramatically how close the two engines' power output are: 298 ft lb @ 2200 rpm (400) vs 342 ft lb @ 2800 rpm (460). At its peak torque, the 400 produces almost 90% of the peak torque of the 460, and it does it at less than 80% of the 460's engine speed. https://www.ford-trucks.com/article/...00_Engine.html

3rd. Proformance Parts Are More Avaiable Than You Think!
Believe it or not but most performance parts made for a 351 Cleveland will fit on a 351M/400. The most important of these is the heads. Any and I mean ANY heads made for a 351C will fit on a 351M/400 with little or no trouble. For a complete chart of the parts that can be swapped click on the link above.

4th. You Already Have A 351M!
Why buy another motor when you have a perfectly good one just begging to be unleashed?


Well I guess it's time to get off my soapbox, but before I go I just want to say that my motor (351M in a '77 F150) cost me about $2000 to get a mild performance rebuild, which mainly was taking off all the crap that Ford saddle onto these things to meet "emission standards". I don't know much about a 351W but from my experience if you want to build a motor for a truck go with the 351M/400.

Most of my information came from the links below.
Main site: http://www.projectbronco.com
Articles: http://www.projectbronco.com/Technical_Articles/Dispelling_the_rumors.htm
http://www.projectbronco.com/Technical_Articles/should_I_Keep_it.htm
http://www.projectbronco.com/Technical_Articles/351m400_performance_build_up.htm

 

What kinda h.p. #'s can be expected from a 408 mild performance build like you describe?

 

What kinda h.p. #'s can be expected from a 408 mild performance build like you describe?

 

well said Mako...

wyazel1 - like grclark said, it is as you build it, so i will speak conservatively...

from a mild 400 build with TMI 9.5:1 pistons and a decent cam you can expect close to if not more than 300 hp and 400 ft lbs...this is not gospel, just my gross estimate

Nick~

 

And would a guy lose any reliability or 'streetability' by building it like that? I've been thinking that I was just gonna swap in a mildly built 460 but after reading all this it kinda makes me rethink. For less money I could just rebuild my 351M as a 408 and get pretty good power. I just want to keep it able to drive to work now and then to show it off, drive up to town now and then etc. 300+ h.p. would be plenty sufficient I think my stock recently rebuilt C6 can handle that just fine. I dont wanna get to radical and start breaking other stuff and have to upgrade or lose streetability.

 

78 F150 4x4 351M C6 4" Lift 35" Goodyear MTR's
^
wyazel1 if this is the truck you are referring to than no you will have no trouble at all with your C6.

I rebuilt my motor before I could rebuild the transmission (short of funds).
I tell you this because it would slip when trying to change gears both before and after I rebuilt the motor, but my point would be that even though my transmission was not working properly it still handled the increase in power with no worsening of the existing problem. I would say that you should see no trouble with your C6 as it has been rebuilt.


My truck is a '77 F150 2-wheel drive 351M (now 359 c.i.) a C6 and a limited slip differential.
We put on an Edlebrock 4v intake manifold with a Holley 750cm carb, new larger cam, Hedman full length headers, and 2.5" dual exhuast with only glasspacks. I did not change the heads or the pistons but I did have them machined and polished. I also did not stroke it out to 408, but I am extremly satisfied with the results. I can burn the tires doing 30 m.p.h., but my favorite part is that "most" people have never heard of a 351M/400 and if they have they believe it to a underpowered smog motor thats better served as a boat anchor.

I even had the guy rebuilding my transmission argue with me over the phone that my motor had to be 351C instead of a 351M because "An M-block just does'nt sound like that!"


I say stick with the 351M/400 not only is it the orginal motor, but I believe it will serve your needs better than a 460 and it will even get "slightly" better gas mileage.

If you want an in depth article about rebuilding a 351M/400 click on the link below. Note: the guy in the article did a lot more things to his engine than I did but he still did not spend more than $3500 on the rebuild)

http://www.projectbronco.com/Technical_Articles/351m400_performance_build_up.htm

 

Thanks for all the advise guys. I am not building a "cookie cutter" 48 Ford pickup. I have already installed an all aluminum Ford IRS and I think rebuilding a 351M out to a 408 would be sweet. I haven't decided on the front suspension yet. Maybe a Valient or Ford just not sure yet. Also considering a T5 tranny. What fun to be creative.

 

Well you might see me on the 48-60 forum, but I also have a 48 F1. I'm going with a 351M/400 for 2 reasons....1: I already have one(ok, I have 3 M's 1 400 and 1 W) and 2: Torque is the name of the game with these heavy-weights(compared to cars anyway) I'm going with the stock beam and reverse eye mains and every other leaf. Probably going the CPP frame mount route and early 70's motor mounts, offset 3/4 " to the P-side and Sanderson headers. Meanwhile I'll be using a TMI 434 kit and will swap the engines when it's ready for final paint....in about 2027.

 

https://www.ford-trucks.com/forums/6...for-400-a.html
looks pretty good on paper!

 

Stay with 351m with the right mods it is a hell of a motor.I have had my days with 351w with my 89-mustang and dont get me wrong great motor but if i knew what i know now about the bottom in torq of 351m i would have ran that motor in my mustang (street car)because really all you want is the horses for a quick punch of the gas at the red light and the 351m has it if built right....351M *******

 

You should get jett's 351M...he has one that is better than any I've seen or heard of...so must be doing something right.

I like the 400. Its a very solid...streetable motor with very impressive numbers and good economy. I'd seriously consider the aussie heads....gives you quench where you can run higher compression with pump 87...or whatever you build for ...cmpression equals power with increased economy.

The torque curve on a mild 400 build will get the torque at or over 400 @ 2000rpm and slightly increase to about 440+- in the mid 3k range. That flat torque curve gets you a very easy rig to drive and use.

I built a windsor using very similar parts...ported heads with 55cc chambers, similar cam, performer intake and exhaust etc and it is no where close to the 400's you see on this forum. The windsor is a great motor and i'd run it before a modified but not a 400.