How to identify a 200 vs 170

[Anonymous]

Hi All,
I'm looking at buying a motor to put in to my 65 Mustang. The motor I'm looking at is from a 65 Fairlane - which looks like it could be either a 170 or a 200. The seller isn't sure what it is. He gave me the casting number from the block which is C5DE6015-H - From the tech pages on this site it looks like it sure could be a 200, but it doesn't rule out it being a 170. Can anyone tell me if we can tell from the block casting number whether it is a 200 or not? If the casting number doesn't do it - how can I tell what size it is? I think one way is the number of freeze plugs - 170 has 3 and the 200 has 5? Is that right, and/or are there other ways to tell?

TIA,
Ben

 

[CZLN6]

Howdy Ben:

Welcome to The Forum. To the best of our knowledge, the C5DE-H is a 7 main bearing 200 engine. But, with FoMoCo we are reluctant to say "Always" or "Never".

Yes, the 200s have 5 freeze plugs, 170s three. Also peer into the cylinder through a spark plug hole. A dished piston is a 200, a flat-top is a 170.

Adios, David