MustangLuvr

Only stay away from the 351 M if you don't want to do any mods. The 351M isn't necessarily a bad engine. It's just a 351C with dished pistons instead of flat pistons. It also has a milder cam than the Cleveland. The biggest difference between the Cleveland and Modified (It's called a "Modified" because it's just a modified Cleveland) is the heads. The Modified heads have a larger combustion chamber. That with the dished pistons give the 351M a very low compression ratio compared to the Cleveland. You could put a more powerful cam and flat topped pistons, and it will make more power. Also any performance mod that you can bolt onto the Cleveland, you can bolt onto the Modified. But you won't really get the performance gains unless you install Cleveland heads. They have a smaller combustion chamber, which raises the compression ratio. Even so, a stock 351M will put out more power than a stock 302. But I'm not sure you would see that perfomance gain at the wheels because of the significantly more weight from the Modified...unless you modded it.

Eric
Boise Id

import slayer

I agree with the above statement but there isn't a very large performance market for the 351m or 400m. It would just cost a lot more to build one....that's all.

bossman351

I have to disagree. The Cleveland and the modified are 2 totally different creatures. The Cleveland is actually a small block and the modified is a big block. The measurement from centerline on the crank to centerline on the cam for the cleveland is lower than the measurement on the modified. Almost 2 inches difference in deck height. The cleveland is more of a small block with bigblock type heads. IMO the modified is junk and none of the parts for a cleveland will work in a modified without significant machine work.

bossman351

Oh yeah, the windsor is an inch wider than a 302 so you will end up needing new headers, intake and a few other things. So be sure thats what you wanna do before you buy it. If it is a Windsor.

tyybo

k this may seem stupid. but uhh dosent it usually say right up on top of the air plenum "302" or "5.0L"?less its carberated. I dont know much bout the broncos

import slayer

I agree with you up until that point. Actually, the cleveland and modified heads interchange. The cleveland heads being much better though.
Both the 351m and 351c are both in the Ford "335" family. The bellhousing in the modified is the same as the big blocks because Ford wanted to keep using the C-6 trannys behind them.

bossman351

No, the modified has a big block bell housing because it is almost 2 inches taller from centerline of crankshaft to centerline of camshaft. Ford made C6 trannys with a smallblock bellhousing. Ive got 2 of them for my Cleveland. Also, yes, the heads off a modified will work but you have to have your intake milled to fit the heads on a cleveland block.

mdvaldosta

easiest way to tell the diff between a 289/302 and a 351w is looking at the deck height (where the heads bolt onto the block) above the top corner of the timing cover. The distance between the timing cover and the deck on a 302 is only a half an inch or so... whereas its close to 2 inches on the 351w - either that or measuring the width of the intake

import slayer

BOSSMAN, check out this link....the 4th paragraph down tells you why the M engines had the big block bellhousing pattern.
http://www.projectbronco.com/History..._ford_351m.htm

bossman351

Doesnt say anything about them changing the pattern just so they could use the C6. only says that it allowed them to use it. And like I said, Ford made a heavy duty C6 in a smallblock bellhousing pattern. I have 2 of them.

^^^That is the true reason for the bigger bellhousing pattern. Ask anyone who knows cleveland motors.


^^^I will admit that youre right on that one, but Im sticking to my guns on the rest. I hope youre not basing what you say solely on that one article. Whoever wrote it wrote it in a fashion to make you believe that the only reason the bellhousing pattern is the same as a big block was for the use of the C6. That is false. As I said twice before Ford made the heavy duty C6 in a small block pattern. So building a motor a certain way for the sole purpose of using a certain transmision would be silly. Dont you think? I would be willing to put my $500 Cleveland up against any 351m/400 you would ever find. And that was not a typo I said $500. I pulled it out of a junkyard for that and would be willing to wager that it is pushing close to 400 hp if not more. Its going in my stang this coming weekend and I'll post pics as soon as I get a chance to get back up to the shop. As soon as it is in and properly tuned its going to Keith Craft to be put on the chassis dyno and I will post the sheet also. It'll be a while till it gets dynoed though.