WHYDTYTT: What Have You Done To Your Truck Today?

[Gary Lewis]

The 351C had a good reputation (as I recall) for performance. I don't have any recollection about it regarding durability. And I have absolutely no experience with it.

The 351M was a good replacement for the 360. By that I mean that both were underpowered, but at least they got poor gas mileage! And both had a really good bottom end, so they both had good potential. But heads, cam, intake and exhaust were poorly executed, so they weren't very good motors from the factory.

I don't know that the 351W was inherently better than the 351M, but it did seem to be executed better (although the 2bbl carb it often came with didn't really do it any favors).

The 351M was developed exactly the way the 360 was - by destroking its big brother. And both were, as you said, underpowered.

The 400 was a good engine, although it had some issues, like the oiling system. But it had great potential due to the size of the ports in the heads - the exact same 2V heads as were on the 351C. However that potential was not utilized as they didn't put a 4bbl carb on it, at least not in the trucks. And they retarded the cam. So the 400 had good torque due to the stroke but ran out of steam quickly due to the carb & cam.

I know a guy that put an Edelbrock intake, 4bbl, & timing set on his stock 400 and claimed it doubled the power. AThe 351M I had with higher compression and the same Edelbrock combo made good power - far, far better than Dad's stock 351M. Dad's 351M/C6 combo got 10 MPG and had no power while the strong 351M & ZF5 got 14 MPG with lots of power - in the same truck.

So I fully agree, those engines were "poorly executed" from the factory. But they had great potential.

[ArdWrknTrk]

The 351C had a good reputation (as I recall) for performance. I don't have any recollection about it regarding durability. And I have absolutely no experience with it.

The 351M was a good replacement for the 360. By that I mean that both were underpowered, but at least they got poor gas mileage! And both had a really good bottom end, so they both had good potential. But heads, cam, intake and exhaust were poorly executed, so they weren't very good motors from the factory.

I don't know that the 351W was inherently better than the 351M, but it did seem to be executed better (although the 2bbl carb it often came with didn't really do it any favors).

The 4V C heads flowed hugely better than the later 2V (M)

Who can forget the Boss 351's we saw in the early '70's?

More compact and higher revving that the 385 engines, they were the weapon of choice in SCCA and drag racing.

Also chosen for the Pantera, Detomaso's semi-factory hypercar that could be found at your Mercury dealer.

[ArdWrknTrk]

The 351M was developed exactly the way the 360 was - by destroking its big brother. And both were, as you said, underpowered.

The 400 was a good engine, although it had some issues, like the oiling system. But it had great potential due to the size of the ports in the heads - the exact same 2V heads as were on the 351C. However that potential was not utilized as they didn't put a 4bbl carb on it, at least not in the trucks. And they retarded the cam. So the 400 had good torque due to the stroke but ran out of steam quickly due to the carb & cam.

I know a guy that put an Edelbrock intake, 4bbl, & timing set on his stock 400 and claimed it doubled the power. AThe 351M I had with higher compression and the same Edelbrock combo made good power - far, far better than Dad's stock 351M. Dad's 351M/C6 combo got 10 MPG and had no power while the strong 351M & ZF5 got 14 MPG with lots of power - in the same truck.

So I fully agree, those engines were "poorly executed" from the factory. But they had great potential.

My buddy Theo has a Boss GT Fastback rotting in his garage.... 😢

At least the garage roof and door got replaced last year, but the damage is done.

[Nickelplate]

The 351M was developed exactly the way the 360 was - by destroking its big brother. And both were, as you said, underpowered.

The 400 was a good engine, although it had some issues, like the oiling system. But it had great potential due to the size of the ports in the heads - the exact same 2V heads as were on the 351C. However that potential was not utilized as they didn't put a 4bbl carb on it, at least not in the trucks. And they retarded the cam. So the 400 had good torque due to the stroke but ran out of steam quickly due to the carb & cam.

I know a guy that put an Edelbrock intake, 4bbl, & timing set on his stock 400 and claimed it doubled the power. AThe 351M I had with higher compression and the same Edelbrock combo made good power - far, far better than Dad's stock 351M. Dad's 351M/C6 combo got 10 MPG and had no power while the strong 351M & ZF5 got 14 MPG with lots of power - in the same truck.

So I fully agree, those engines were "poorly executed" from the factory. But they had great potential.

As far as 351's go, I have had a bunch of 351C, a couple 351W, and almost no 351M (and 400). The 351C is an absolute torque beast in any configuration, the 351W has great potential, and I love the SBF familiarity factor. The 351M and 400 seemed like any other late 70's engine that had been nerfed for fuel economy and emissions. Those last two ALWAYS had open chamber heads, but it was the same design as the 351C, for which there were multiple versions of closed-chamber heads made. A closed chamber swap on a 351M or 400 would be an instant compression boost, as well as getting you much larger valves and ports.

[Gary Lewis]

The 4V C heads flowed hugely better than the later 2V (M)

Who can forget the Boss 351's we saw in the early '70's?

More compact and higher revving that the 385 engines, they were the weapon of choice in SCCA and drag racing.

Also chosen for the Pantera, Detomaso's semi-factory hypercar that could be found at your Mercury dealer.

Yes, the 4V heads did flow well. But the ports were huge and that killed the torque at low RPM.

But the 2V C/M heads had pretty large ports themselves, much larger than the Windsor heads. Brandon/Bruno2 came over one day to pick up a pair of W heads I was giving him. He's a good sized guy so I told him where they were in the attic. But he came down with a pair of 2V C heads. So I took him, carrying the heads, back up and showed him the W heads. He said "Wow! They have such small ports!" Yup.

[Nickelplate]

The 4V C heads flowed hugely better than the later 2V (M)

Who can forget the Boss 351's we saw in the early '70's?

More compact and higher revving that the 385 engines, they were the weapon of choice in SCCA and drag racing.

Also chosen for the Pantera, Detomaso's semi-factory hypercar that could be found at your Mercury dealer.

I have a few sets of Pantera 4v 351C heads right now (one of which I'm trying to sell, unsuccessfully). They are badass. They are the same casting as the Boss 351 heads, same ports, valvetrain, valves, and chamber cc.

I'd probably consider them wasted on a 351M or 400, but I bet they'd be a huge improvement over stock!

[ArdWrknTrk]

I have a few sets of Pantera 4v 351C heads right now (one of which I'm trying to sell, unsuccessfully). They are badass. They are the same casting as the Boss 351 heads, same ports, valvetrain, valves, and chamber cc.

I'd probably consider them wasted on a 351M or 400, but I bet they'd be a huge improvement over stock!

I had a buddy in Florida who owned two Pantera and a gold head E-type Jag.

Somehow all of them died of neglect when he hopped on the crazy train. (this is the same guy who got his AMX stuck so high in a tree he needed to hire a crane and a tree surgeon to recover it!)

Wild times!

[85lebaront2]

The 351M was developed exactly the way the 360 was - by destroking its big brother. And both were, as you said, underpowered.

The 400 was a good engine, although it had some issues, like the oiling system. But it had great potential due to the size of the ports in the heads - the exact same 2V heads as were on the 351C. However that potential was not utilized as they didn't put a 4bbl carb on it, at least not in the trucks. And they retarded the cam. So the 400 had good torque due to the stroke but ran out of steam quickly due to the carb & cam.

I know a guy that put an Edelbrock intake, 4bbl, & timing set on his stock 400 and claimed it doubled the power. AThe 351M I had with higher compression and the same Edelbrock combo made good power - far, far better than Dad's stock 351M. Dad's 351M/C6 combo got 10 MPG and had no power while the strong 351M & ZF5 got 14 MPG with lots of power - in the same truck.

So I fully agree, those engines were "poorly executed" from the factory. But they had great potential.

One issue with the 351M, 400 Fords and also the 400 SBC, was heat. All of these engines have "siamesed" cylinders in order to fit the large bore into the block constraints. The Ford engines are (bore first then stroke) 351C 4.0 X 3.5 = 351.8592 ci, 351M is the same, 400 4.0 X 3.98. Chevrolet 400 4.125 X 3.75 = 400.92216 ci was in a block originally designed for the 283 3.875 X 3.0 = 283.0386 ci (265 didn't have an oil filter provision, might have gotten one later).

On the shorter stroke 351M the siamesed cylinders didn't seem to be an issue, and even the Ford 400 didn't have a bad heat problem, the Chevrolet 400 possibly had one. Biggest issue with the Ford engines, the 400 was built to replace the 390, which by 1970 was reduced to a 2 barrel only, and was a mid 1950s design and was going to have problems with the upcoming emission requirements, they were set up so lean they barely ran, and the huge ports of the Cleveland heads didn't help.

The 351M and 400 were built to share their back of block bolt pattern with the 385 family (429/460) but in a shorter package. This allowed Ford to use the existing 385 family transmission or clutch housings reducing the number of different parts. The unfortunate problem with both the 351M and 400 was the lack of power and horrible fuel economy. Ford spent three years (1980-1982) building trucks with the 400 being the biggest availble engine. It hurt them badly in the towing market after having the 460 available from 1975-1979. Since the new body and chassis introduced for the 1980 model year was toughted as being smaller frontage for better economy, there almost wasn't room for the 460 due to it's size. When I sent Gary a picture of Darth's engine compartment, his first question was "how high up did they have to drop it from to get it in?". He knows now, and I think he understands why I don't want headers on Darth.

 

[ArdWrknTrk]

One issue with the 351M, 400 Fords and also the 400 SBC, was heat. All of these engines have "siamesed" cylinders in order to fit the large bore into the block constraints. The Ford engines are (bore first then stroke) 351C 4.0 X 3.5 = 351.8592 ci, 351M is the same, 400 4.0 X 3.98. Chevrolet 400 4.125 X 3.75 = 400.92216 ci was in a block originally designed for the 283 3.875 X 3.0 = 283.0386 ci (265 didn't have an oil filter provision, might have gotten one later).

On the shorter stroke 351M the siamesed cylinders didn't seem to be an issue, and even the Ford 400 didn't have a bad heat problem, the Chevrolet 400 possibly had one. Biggest issue with the Ford engines, the 400 was built to replace the 390, which by 1970 was reduced to a 2 barrel only, and was a mid 1950s design and was going to have problems with the upcoming emission requirements, they were set up so lean they barely ran, and the huge ports of the Cleveland heads didn't help.

The 351M and 400 were built to share their back of block bolt pattern with the 385 family (429/460) but in a shorter package. This allowed Ford to use the existing 385 family transmission or clutch housings reducing the number of different parts. The unfortunate problem with both the 351M and 400 was the lack of power and horrible fuel economy. Ford spent three years (1980-1982) building trucks with the 400 being the biggest availble engine. It hurt them badly in the towing market after having the 460 available from 1975-1979. Since the new body and chassis introduced for the 1980 model year was toughted as being smaller frontage for better economy, there almost wasn't room for the 460 due to it's size. When I sent Gary a picture of Darth's engine compartment, his first question was "how high up did they have to drop it from to get it in?". He knows now, and I think he understands why I don't want headers on Darth.

Heat can definitely be an issue if you don't know enough to demand the proper thermostat.

Unfortunately Ford in one of their crackhead moments didn't decide to make them entirely incompatible with the Windsor.

(Yes, I understand the advantages of commonality wrt springs and wax pellets, but you'd think a three bolt flange could have a shape like a Wankel rotor or something, so they couldn't be mixed)

[FordFETruck]

But my gosh that 400 was in a lot of cars and trucks back in the late 70's - early '80's

I don't remember many being broken either.

Maybe I'm too young to have been paying much attention.

Maybe they were just the right balance of torquey and underpowered to keep from self destructing?

Certainly the 351C had a reputation!

The Carolina van looks like a really cool glamping rig.

I'm drooling over all that shop space and wondering what the interior window/passthrough is for?

My grandparents had a 77 F150 trailer special with a 351M they bought when it was only a few years old. The 351M in that thing was worn out clattering garbage at 79,000 miles and not even 10 years old when my grandpa rebuilt it. On top of that, it had chronic loose steering and wandering problems that nobody could seem to fix. He bought a 1990 F250 extended cab 460 auto truck brand new after that one, seemed to be a much better truck. The 77 replaced a 66 F100 352 automatic he had for years and used for work, think he was better off with the 66.