[ditneal]

I need help to locate the engine #'s on a Ford 351. it's in a 36 Ford so I'm not sure of the year either. I'm trying to determine if this is a small or big block and if it's a cleveland, windser, or modified. the only #'s I can locate are next to the water pump and they are 3C 8G.

[66GMC]

Look under the ignition coil for an ID tag.

351W had:
6-bolt valve covers
Coolant bypass hose from thermostat housing to WP
Thermostat housing mounts horizontally
Fuel pump bolts aligned horizontally

351C had:
8-bolt valve covers
No bypass hose on thermostat housing
Thermostat housing mounted vertically
Fuel pump bolts aligned vertically

The terms "big block" and "small block" don't really apply here either.
Based on the transmission bolt pattern, 351C/W are both "small blocks"

You may even have a 351M in there. Their characteristics are similar to those described above for the 351C, but they have the "big-block" transmission bolt pattern (same as 400/429/460)

This has been discussed here (hotrodders.com) many times ... search thru the engine section, and I'm sure you find lots of good information.

[xntrik]

W series engines the thermostat is in the intake manifold, C and M are in the "timing cover".

W and C engines bolt in like small blocks.

M series engines bolt in like big blocks; use big block engine mount pattern as well as BB bellhousings.