351 Clarification

[AZKen]

Questions about a motor stamped 351. But that's it. No M, no serial. So what exactly is it? Two bolt I beam exhaust.

[Ed Snyder]

Originally Posted by AZKen

I looked at this motor and see it's stamped 351. But that's it. No M, no serial. So what exactly is it? Two bolt I beam exhaust.

Probably a replacement 351C. The 351C in my '65 one ton Suburban is the original engine, and has no "C" after the 351. I think replacement engines sometimes had no serial number.

[AZKen]

About a 67-68? pretty special. Spin on filter, power steering, AC, Alternator, perch mounts, "Iron Maiden" exhaust manifolds, double groove pulleys all around. Clean and a few odd things I haven't seen. Is it a magnum? Need to know before I offer to someone.

[BobBray]

Sounds like a 351E except for the exhaust manifolds. Is the AC compressor mount for a Fridgidare A6 on the right side outboard of the alternator? Low or high mount power steering pump? Maybe a replacement block for a 351E in a pickup.

[AZKen]

Compressor right. P/S left.

[AZKen]

Was reading in our archives and it says magnum 351 has trapazoid carb manifold mounting pattern. This 351 has that. Jolly pages says some had just 351 with no letter stamped. Pretty sure this is a magnum. Sclor is an expert on these it seems as well as Lewis and a few others. Mine has the spin on oil filter, so probably 1968'ish and up motor.

[LEWISMATKIN]

IF is in a pickup, it more than likely a 351E, which carries no oil-driven govener. the 351M, like the 401,M, 478,M had the oil-driven governed version of the WWC. if the 351 were equipped with the WW, it would be an early 351 or a 351C.

[AZKen]

Hi Lewis, it had no carburetor when I got it. I happen to have an aluminum adapter that adapts from trapezoid to rectangular carb bolt pattern. So I added a regular WW for now. Not Kosher but it may work to just start motor. The bottom line is the manifold has trapezoid bolt pattern and is original to the motor. There is something, like a black box, under the manifold. Have not examined yet. At a glance, thought is was something someone stuffed in there for transport. Will examine that anomaly soon. Of course, you know it has the I-beam exhaust manifolds.

[Prowbar]

If it has the governor it should have the big truck oil pan, it is deeper and has a different angle and shape compared to the pickup pan. Another clue is if there is an oil line running to the place of the carburetor, it comes from one of the 1/8 NPT ports on the block next to the oil filter and runs with a 5/16" line to the carb base.

Another clue to check for truck vs. pickup is the timing cover.

A third clue is whether there is a stud installed in the block on the passenger side motor mount area, these are used on the pickups but not on the bigger trucks.

[AZKen]

No reason to determine big truck or pickup

From our own Jolly pages and archives:

" The 351E V6 which was available from 1966 to 1968 in 1/2 to 1 ton trucks is essentially a
Magnum engine, as it has the big port heads & bigger manifolds. If you ever run into
some old magazine adds from 1966 it mentions the 351 Magnum engine available as
a high performance option. The 351's were available both as Magnums & small port
head 351C engines up to 1972."

"Attached are the two carb bases for magnum and non magnum. The magnum trapezoid base is marked 60053 in the picture. If you have the manifolds for the 351, then the carburetor might be the only thing that wouldn't swap from 305 to your 351 without an adapter plate."

Right now I'm calling it a 351 magnum. In the daylight, the "black box" was a VR stuffed in there.