I have a 1979 F150 and has a 351M, Any info on the motor would me helpful. Someone told me that it is a big block and others told me that it is the same as a Cleveland and Windsor. The motor runs great, I would just like to know more.

Joe

 

The modified is actually a small block V8 but has the bell housing bolt pattern of the big block 429/460. The 351M uses the same block as the 400M but with a shorter stroke. Where as the 400M has a 4.00" stroke the 351M uses a 3.50" stroke. The 351M was produced after Ford stopped making the Clevelands in 1974 to keep up with the market demand for the 350 cubic inch class. If I'm not mistaken there is section here on FTE that tells about the Modified engines. It's called Hight Performance Options for the 351M/400 Engine. You should read through that. It has a lot of good and useful info on the modifieds. Hope this helped some.


Robert

1978 F-150 4x4 Stepside 351M

Please don't pull out in front of me! The last thing I want to do is play identify the pieces with you or your car.

 

Here's the link to the article:

[link:www.ford-trucks.com/articles/mblock.html|High performance options for M Blocks]

 

351m is actually a 400 block with the 351C crank installed. That gives the 3.5 stroke. however since the deck height is for the 400 4" stroke different pistons are used. the pistons have the pin lowered .250" to bring the piston to the top at TDC. Yot can make it a 400 very simply. Buy a 400 crank, 400 piston, 400 vibration damper for the front and a new 400 flywheel.
I did that. if you do the same when you assemble is check the location of the piston at TDC. The old smog engines had about .125" of extra blosk height. that results in VERY low compression ratio. I planed my block to give .020 to .030" clearance. gives about 8.75 to 1.
If you want to get really strong I'll tell you the rest. I've got about 80,000 on my hot one and running great.

 

Uh no. The 351C has much smaller mains than the 351M/400 which are the same size as the 460 (3")

 

Right on Bill. Also that extra depth the piston sits down in the hole contributes to preignition. I found I could run more compression with less ping by using a taller piston.

1977 Ford F-100
400m/c6/4:11/Gear Vender O.D.
Crane hydralic roller, forged, ported polished,Deamon,Edlebrock, yada, yada, yada
280,000 miles
Stock on the outside
modified/rebuilt everything

 

Hmm...

I wish I still had my old Torino...
Or even just the spec's for the crank from the machine shop.

Did any of the 4V 351 Clevelands have 4-bolt mains?

 

>Did any of the 4V 351 Clevelands have 4-bolt mains?

Yep they did. '71 Boss & CJ, '72 HO & 4V and '73 4V had 4 bolt mains. Any 2 bolt block can be made into a 4 bolt block with the right caps and some machining.

 

Bill Perhaps you can e-mail me some info on how to build a 400 with 4-bolt mains and about 9.5 compression,bigger valves and good heads i want to build a 460 killer and most of all a ch*vy 350 killer.

I am new to the 351/400m engine family. I want to rebuild my 351 making it a 400 the right way and i always see your replies and see you know probly everything there is to know about them, and just wanted to hear your input.

My email is gravedigger4x4(No Email Addresses In Posts!)

also do you have AOL IM or anything that I could chat to you on?

 

>Bill Perhaps you can e-mail me some info on how to build a
>400 with 4-bolt mains and about 9.5 compression,bigger
>valves and good heads i want to build a 460 killer and most
>of all a ch*vy 350 killer.

I can direct you to the Hot Rod article where they built a 382 hp, 456 # torque 400. It gives specs on all the parts they used. I would substitute Ohio P&P flat top pistons (p/n 1282P) for the dished pieces they used. I used those pistons in the 400 I built. I haven't got mine to the dyno yet but I think it'll be close to those numbers.

[link:home.earthlink.net/~tcrocker/400.html|Hot Rod 400 Build Up]

As far as the valves, the 2V & M heads will take the bigger Cleveland 4V valves with the appropriate machining. I didn't do it in my engine but I kinda wish I had now. They didn't do it in the HR engine either.

The only other thing you need to make a 351M into a 400 is the crank. I've never seen a 400 4 bolt and Ford didn't make 'em so I think you're outta luck unless you want to pay some major $$$ for custom caps and the machining to make 'em work. Frankly I don't think you'll need 'em, the bottom end of the 400 is plenty stout especially if you have a D7TE or D8 block casting.

I don't have AOL messenger but we can use the chat room here if you want to set up a specific time.

 

Thanks for the info and the quick reply!

as for getting my crank I was thinking of one from PAW. Any other suggestions on that?

 

>Thanks for the info and the quick reply!
>
>as for getting my crank I was thinking of one from PAW. Any
>other suggestions on that?

PAW has treated me pretty well. I got lucky and happened to find 1 on eBay of all places. The only other places I can think of are a junkyard and making friends with your local machinist.

 

I view the small/big block terminology as Chevy centric an irrelevant to Fords...

The 351C/M/400 are all based on the same design, the later 2 have a different bellhousing and deck heigth.

Trying to fit the Ford engines into two categories is an excerise in futity, but if it must be done, Bore spacing is a better method.

Sorry for going off on this subject, but it is fustrating to see us try to conform to that brand X terminology!

1970 Mustang Grabber Sposrtsroof. Rather non-stock...
1965 f100