I recently got a 1978 f150 4x4 with a 351 engine. Does anyone know how to tell wether it is a m or c?


Trevor

 

[font size="1" color="#FF0000"]LAST EDITED ON 16-Jan-01 AT 06:20 PM (EST)[/font][p]If engine hasn't been changed, its a 351M. Ford did not put Clevelands in these trucks.

"Nothing lasts forever except natural stone and old Ford trucks." (Willie Nelson)

 

Just look at the valve covers. If they have a weird shape to them then it's a M

 

sycoclwn,

Weird shape? Obviously, you are unaware that the 351C and 351M use the same valve cover.

BubbaF250

1980 F250 4x4 Custom, 351M/NP435/NP208/D44HD-TTB/D60-FF/3.55s 6750 GVW, Rust & White.

 

If your motor is original it should be a 351 modified or
a 400. Does your drivers side valve cover still have its
original engine id sticker? If it is still intact it will
tell you what it should be.

GLENN

 

Hey, I have a 351 C in a '78 Ford F 100 Custom, I read the way you can tell the difference between an M, or W is the Valve cover Bolts, 351 C's only have 5 bolts for valve covers while the M, and C's both have 8. I just rebuilt my engine and on the pistons is says 351 C right on it so if you plan on rebuilding you're engine that's another way to tell

 

>Hey, I have a 351
>C in a '78 Ford
>F 100 Custom, I
>read the way you can
>tell the difference between an
>M, or W is the
>Valve cover Bolts, 351
>C's only have 5 bolts
>for valve covers while the
>M, and C's both have
>8. I just rebuilt
>my engine and on the
>pistons is says 351 C
>right on it so if
>you plan on rebuilding you're
>engine that's another way to
>tell

blaxuede,

I assume you meant to say the 351W has fewer valve cover bolts. The 302/351W have 6 valve cover bolts, the 351C/351M/400 have 8 valve cover bolts.

It only takes 10 minutes to change a valve cover, so valve cover ID tags are not very reliable.

BTW: 351C pistons will work in a 400, so piston ID is not necessarily a sure way to tell either.

You can distinguish between the 351C and 351M/400 engines by the block casting number, located on the side of the block, under the rear of the right cylinder bank (just above where the starter mounts).

Both 351M and 400 engines use the same blocks. The most certain identification of the 351M/400 engines is the crankshaft casting number. In fact, identifying the crankshaft is really the only way to positively distinguish between the 351M and 400, as all their external components are the same.

Another way to distinguish between 351W and 351C/351M/400 engines is the location of the thermostat housing.

The 302/351W have a "wet" intake manifold, with coolant flowing through the manifold. The 302/351W thermostat housing attaches to the front of the intake manifold (like FEs and 429/460 big blocks).

The 351C/351M/400 engines have a "dry" intake manifold, with no coolant flow through the manifold. The 351C/351M/400 thermostat housing attaches to the top of the block, in front of the intake manifold.

BubbaF250

1980 F250 4x4 Custom, 351M/NP435/NP208/D44HD-TTB/D60-FF/3.55s 6750 GVW, Rust & White.