Will a 351M fit an EB

[Tuff68]

I have found a 1977 351M ( Cleveland ) with 400 heads that has been rebuilt from top to bottom with the best of everything and a C6 trans that has also been rebuilt.
The owner built it for a project Ford truck the ended up being sold.
The motor and trans are mine for just the price of having it shipped to Tennessee but only if I use it in my EB.
??? From what little I know about it the 351M is a big block and I don't know what if anything can be done to make it fit.
Does anyone run the big block in an EB and if so how much extra is required to make this kind of change.

Thanks to all,
David

 

[IowaMike]

Would involve the same steps as putting a 351 Cleveland in. Cs & Ms are in the same family.

 

[jon cook]

77 bronco 400/351m

yes it works great. crossmember and drive shafts

 

[Apogee]

Not worth it...most people swap out 351M's for 429/460's because they're a better engine IMO, not to mention about the same size. I won't get into the argument that the engine is technically a small block...because it's physically rather large. The 400 is a much better starting point for torque if you really want to go that route since the only difference between it and the 351M are the crankshafts and the pistons.

I had the choice to rebuild my 351M in my pickup and I swapped in a 429 instead (same bellhousing pattern) and traded the running 351M for about $75 worth of exhaust work, which tells you about how much they're worth where I live.

You can squeeze 429/460's into EB's so I'm sure you can fit a 351M/400...but I think you'd be happier with a small-block in the long run or go all out and get a real big-block.

 

[broncnaz]

There's a few guys running them mostly built strokers though. there's nothing specail about 400 heads as they are the same as the 351M heads and thats the major draw back with the 351/400 engines there heads suck and they ping easily. Your other big problem with swapping one in is exhaust I think most have a custom one made. I second the notion to stick with a small block engine 351W is a much better choice as far as fit and hop up parts.

 

[73stallion]

just to clarify, the 351m uses a big bellhousing (same as a 460). the motor mounts are also different. i wouldn't waste the time, just do a 351w.

 

[Devin]

I used to think that the motor mounts were different also....until this thread:

http://classicbroncos.com/forums/showthread.php?t=78923&highlight=351M

 

[bax]

The motor has the same features as a 351c. It uses the same motor mounts as a 351c and a 351W so it is a bolt in. It is also a small block and yes it is in the c family. However there are a few diferences. It has a big block bell housing bolt patern. This is not a big deal if you already have a trans you like that uses that pattern. It also has a larger main bearing journal, so 351c and 351m cranks do not mix. This is no big deal. 351c and 351m and the 400 all use the same head. However the 351c is the only one that used a performance head. Aussie heads on the 351m would be a great addition. The 400 is the motor of choice between the two. It's kinda like a 351M stroker, if you want to go that far. Sanderson makes a header that fits it too. Yes your 351M will go into your EB.

Bax

 

[SaddleUp]

There is at least one member here that runs the 400M and has installed a few of them. Find out what changes he had to make and that will match the changes needed for the 351M. As mentioned already the motor mounts are the same as the 351W (Or at least it will bolt directly into the 351W frame towers) and it uses the big block bellhousing. The other definate issue to deal with is the exhaust which will be right on the frame. Not sure how they are getting around that though. Are they going over the top and outside the frame? Are they having custom headers built? etc. The only 351C I've seen in one had the exhaust up against the frame.

 

[Tuff68]

Thanks for the info

Thanks to all for the info. Looks like making a swap to the 351M is more of a job than I will be able to do with my limited mechanic skills.
Was hoping it would not require a lot of extra work, and I just put a custom exhaust system on my EB and would not want to spend the $$$ to redo it.

 

[bmc69]

Putting a 400 in my '69 was the single best thing I have ever done to any of my EB builds, with hydroboost in the running for that honor also. Fitting it in is not much of a challenge if you have the body off to begin with. A 2" body lift is pretty much an absolute requirement also. The motor bolts straight up the factory EB V-8 frame mounts using stock 351m/400 motor mounts.

Why a 400?. First, its a great engine foundation to start with, common lore and misconceptions notwisthstanding. Second, with a set of (cheap) closed-chamber iron heads, the right cam and internal mods and an EFI on top..you get a '408' torque monster that costs little more than half what a comparably performing 408W costs. Even if you start with a 351m and (this is a requirement BTW..;D ) have to convert it 'back' to a 400 with new crank and pistons, its still a cost-effective option.

Because the '408C' is a factory "4.030 x 4.0" configuration, piston stability/ring locations and rod ratios, etc are much better suited for a long-lived motor than the case for a stroker 408W. Weighs exactly 65 pounds more than the Windsor..so no big deal there. The 460 weighs considerably more than that and is a bigger challenge to stuff in an EB by far.
The center section of the cross-member does need to be modifed, said modifications depending on what tranny and t-case you use as well.

 

[bmc69]

Fits like a glove (well..OK..maybe like one of OJ's gloves.. )

 

[RRRAAAYYY2]

No offense to anyone that has done in the past, but my opinion is that the 351M motor is best used as a boat anchor. The last one I ever will own i spread all over the interstate in Ill., in the middle on an ice storm, 15 hours into a road trip. A 460 will get you the same gas mileage, a lot more torque, and will handle higher rpms.

 

[cjjhalfcab]

Kind of a shame when you get more "nays" on putting a Ford engine in a Bronco than if you brought up putting a 350 Chevy in it.

I'm with bmc69; run it out to a 400 and you'll have all the torque you want without having to drop a bunch of money on a stroker crank and aftermarket heads so a Windsor can breathe. A guy on the Cleveland board has a 400 with the FMX block in an EB, and he really likes it. That engine was (I believe) originally destined for a Cobra kit car. Sat to high or something, so it went in the Bronco.

Remember, until the "five point oh" ressurected the Ford small block, the 351 Windsor wasn't even a performance consideration. Now that there are all kinds of alloy heads, etc., showing up for the 335s, the 400 may have it's day in the sun.

 

[bax]

Add me to the yes list. Cjjhalfcab, too much information. Your going to make them too hard to find.

Bax

 

[Frankenhorse]

Dave, I would love to do that swap. I also know where you are at with putting it in so I say you'll be happier rebuilding yours or getting a 351w. I think it is more work than you want to do.

 

[SaddleUp]

No offense to anyone that has done in the past, but my opinion is that the 351M motor is best used as a boat anchor. The last one I ever will own i spread all over the interstate in Ill., in the middle on an ice storm, 15 hours into a road trip. A 460 will get you the same gas mileage, a lot more torque, and will handle higher rpms.

I refrained from saying the same thing as I didn't want to offend those that seem to theink the are great. (I have said it in the past though) Personally I think a small block windsor motor is all an EB needs if it is set up right. I have plans for a stroker motor myself but I'm going to stretch the stock 5.8 as far as I can first. At the rate I'm going it might last another 10 years.

 

[cjjhalfcab]

I refrained from saying the same thing as I didn't want to offend those that seem to theink the are great. (I have said it in the past though) Personally I think a small block windsor motor is all an EB needs if it is set up right. I have plans for a stroker motor myself but I'm going to stretch the stock 5.8 as far as I can first. At the rate I'm going it might last another 10 years.

I can agree on a properly built 351W being all it really needs. I also try to refrain from offending folks, but to me there are too many that feel like quarter mile engines belong in four wheel drives; the 400 was made for heavy cars and trucks. 408 stroked Windsors are typically built for racing, not rock crawling. Properly built I don't see a problem, but from a lot of the builds I'm seeing they are building Mustang engines, not Bronco engines. Big difference. But then there are more and more guys putting stroked-out "junk" "boat anchor" 400s in Panteras. Kind of a high-class caliber car to be putting trash in, I think. Maybe those that can afford exotic Italian sports cars aren't as educated.

I don't think the 400s are necessarily "great", but don't think they are any worse than a 351W. I think too many have driven the retarded-timed, low compression 351Ms and 400s and made up their mind by those.

 

[bmc69]

The Cleveland foundation of the 400 engines, with 'modern; oval-port large-valve free flowing heads and intakes, good block design (except for easily -fixed oil system deficiency) is superb and well-known to those of us that have been building perfromance 400s for a long time. The 400 was designed in 1969/1970...the last and most advanced pushrod engine ever designed by Ford. Unfortunately for Ford..Uncle Sam's emissions requirements snuffed it almost right out of the starting gate and only the very first year engine - in '71 - was delivered with the 'juice' that they were even remotely capable of.

We build FEs, Windsors of all kinds, and 429/460s...they all have a place in the various performance applications we build for. All I'm saying is that the 400, properly built, is a superb EB engine and fits in a lot easier than the heavier and larger 460. For those that missed my earlier psots, the 400 in my '69 achieves 496 ft-lbs at the flywheel at just under 3000 RPM and ..beat this with anything but a diesel..457 ft-lbs at 1500 RPM!. Now that is good trail thumper material.

The 351m is simply a crudely destroked 400. Not worth fooling with in stock form, since its so darned easy to turn one back in to the 400 from whence it came.

The Pantera guys are going for the 400s beacuse they can't stroke their Cleveland 351s out that far. The 400 can and is stroked to 434..that last PAntera 434 built that I saw dyno numbers on (have the video too..) was nearly 500 x 500 on torque and HP (flywheel) and ran on pump gas. And the torque curve was incredibly flat throughout the RPM range.

 

[bmc69]

Hre is a cut from the dyno report on that 434 stroker...silly numbers; the torque curve almost looks faked, it's so flat. Note that the peak RPM is anything but low..