Ok I may be buying a 1978 F-150 4X4 tommorow. It's a really nice truck he wants $1800 for it. And it has "Newer" paint on it and lots of new parts. But anyways it has a 351 in it with a big 2-BBL Carb. I don't know very much about older vehicles and neither does the guy who's selling it.

I was wondering is this motor a Big Block or a Small Block? It's the original motor that came in the truck. It fills up the entire engine bay and looks bigger than my 302 but I can't tell for sure. What usually came in these trucks? BB or SB?

Thanks!

------------------
1993 Ford F-150
Kustom Kreations Package
2WD, 5.0 (302), AOD, 3.55

K&N Drop In, Superchip, Dual 2.25" Exhaust,TransGO Shift Kit & Pirelli Scorpion Zeros!

Eclipse CD Player, Eclipse 8-CD Changer, Eclipse Amp, Clarion front speakers, 8" Boston Acoustics Subwoofer

Future Mods: STEEDA Suspension Kit & Some More Engine Mods!

 

BMW325
I Had a 78 F-250 and it had the 351M engine in it. It also had a big 2-BBL Carb on it.
If I had to guess I would say it is the 351M but without seeing it I am not sure.

------------------
1999 F150 4x4 4.6V8 regcab/shortbed
Oxford White with Wedgewood Blue two tone, with Blue Captains chairs
Bassani Cat Back, Superchip,Modified intake with modified K&N filter.
Centerline Saber rims 17x8" with Firestone GTA 275/60hr-17 tires.





[This message has been edited by Don C (edited 03-31-2000).]

 

The 351 is a small block. It is related to the 302 and the other small block Fords in that the space between the center of each bore is the same. The 289, 302 and 351 all have the same bore, 4". The 351 has a longer stroke. Therefore, the block is "taller" as each arm of the block's "V" is 1/2" longer than the 302. This makes the intake manifold and the hole engine wider.

Its a good truck engine when healthy, but noted for poor mileage.

Big Block Fords are the 460, 429, 428, 427, 390 and the 360.

 

DirtBike: I thought that the 351M, 351C and 400 where all Big Blocks?

[This message has been edited by BMW325 (edited 03-31-2000).]

 

They have bigger heads & valve covers than the Windsors, so they look bigger. Also, the timing chain covers/water pumps are different, so almost all the stuff that is easy to see looks bigger/different. But the block length and bore spaceing of the M and C are same as the Windsor small blocks . You can even put the Cleveland heads on the windsor blocks - head bolt pattern is the same. I'm not saying you can interchange everything between the W, M & C, but they are all considered small blocks.

[This message has been edited by dirt bike dave (edited 03-31-2000).]

 

My buddy in highschool had a 78 f-150 with a 351m and a c-6. Not alot of speed, but it could and would pull a house down. I would go for it anyways BMW. The 78-79 Fords are very popular trucks. That was the last time Ford used a solid front axle on a 1/2ton pickup. Even if you don't like it, if its in decent shape, you may be able to sell it for more money later on.

FYI,Its to my understanding that the modifieds are considered big blocks, probably because of the big block bolt pattern. Basically the 351m is a de-stroked 400. Dave is right, they get very poor mileage, and I've heard they suffer from poor oil curculation and overheat. Ford used them up to and including 1982. Ford replaced the 400 with the return of the 460 in 1983. From then on out ford used the windsor series. Here's some notes from another page.
Also, Ford's tech manual for 78 351m's stated 145hp@3400rpm
273ft/lbs@1800rpm.

Im not sure if this would be rear wheel or fly wheel.
**

 

All '78 Ford Trucks with a 351 had the 351M. It is not considered a small block like the 351W. I have heard some people say the engine has oiling problems, but my experience has been its a good truck engine if you maintain it. We had the same truck when I was in high school and installed a dual plane 4 barrel intake and Holley 600 carb (non EGR). It really woke the truck up off the line. Passing power was still flat because of the stock camshaft. The truck ran great until 130,000 miles when it got wrecked. Used a quart every 3k miles. Believe it or not, my dad still has the engine and trans in storage. It was just to good to give to the junkyard with the aftermarket intake and everything!

[This message has been edited by Tenderpaw (edited 03-31-2000).]

 

The 400/351M are spun off from the Cleveland. My dad's two '78 F150 4x4's, both with 400's and automatics, get 10 mpg driven nicely. That might have something to do with the Holley 500cfm 2-bbl carb on one of them though. They've been good engines for us over the years.

 

You guys rule hehe. Thanks for all the great info. Special thanks to pastmaster for the HP and TRQ ratings.

If I get the truck then I was thinking of putting a small 4-BBL carb on it and a nice intake. But what kind of intake would fit the motor? Would a 351W intake fit it?

Thanks everyone!

 

bmw,
If I had to guess I would say it's the 351/400. It's a big block 351 with 400 heads. It's real low compression, not alot of HP, but it does have plenty of pulling torque at low rpm's. I had one in a '76 f100. I personally didn't like the motor, but you can put a few coins into it and wake it up pretty easy.

------------------
'97 Ford SC 4X4 XLT Off Road pkg., 4.6,A/OD, 3:55, premium sound w/CD chg, Black clct,towing pkg., hvy duty elec. pkg., Bridestone dueler AT's, line X, Flowmaster true duals, chip, K&N air filter, smittybilt stainless nerf bars

 

BMW - you may be pretty limited regarding intake manifold selection - a 351W will not fit.

It is my understanding that the 351M and 400 were developed out of the 351C small block engine in the late 1970's. I've never heard them referred to as big blocks. I'll bet a naked 351M block is closer in size to a 351W block than it is to a 429 or 460 Ford!

 

351M owners - there is a great tech article on a competing website - www.ford-trucks.com. Check the technical articles - Building a 351M for performance.

Regarding the "is it a small block or big block?" question, the answer is small block, but with an asterisk. If ever there was an "inbetween" block, this is it.

The 400M was developed from the 351C small block in 1971, and has the same bore centers and interchangeable heads, cams & other parts. The tech article has a complete list of the 351C parts you can use.

The block's deck height (the length of each arm of the engine's V) is 1" longer than the 351C, but the blocks are similar in most other respects. The 351M has the same block as the 400M, so it is taller than the 351C or 351W.

As stated by Pastmaster, the 351M & 400M have the same bolt pattern for the bellhousing as Ford's big blocks, which allows them to use the same trannys as the big engines.
Originally, the 400M was intended to power the big cars, so it was designed to be hooked up to a C-6 auto tranny.

The 351M was first used in passenger cars in 1975, and in trucks from 1977.

Sorry for the long post.

 

Cool Dave! Thanks for the info and the link to the article. Lots of good info in that article it has helped me understand the engines a great deal more

Thanks!

 

My 78 F-150 custom has the 351m with 2barrel carb. The 351m/400 has the same belhousing bolt pattern as the 429 and 460. The Cleveland and Windsor motors what a bolt pattern with 289/302. Defining motors as bigblock or smallblock is a Chevy thing

 

You brought up a 17 year old thread just to say that?