My '66 has a 351 Windsor installed that some prior owner installed and I would like to know more about it. The air cleaner indicates that it is a 351 High Performance engine, is there such a version of the 351? Also, is there a way that I can determine when the engine was manufactured, serial no. etc. and where do I find such a number. Thanks.

 

There is a part number that is cast in to the bottom of the block under the starter but I don't think it's going to tell you much.

There really isn't much difference between one 351w and the next as far as the factory blocks go except maybe roller vs flat tappet.

The easiest way to tell the difference between a 302/289 and a 351w is the deck height. A 302's heads look like they are sitting right on top of the timing cover and a 351w will have about an inch between the timing cover and the head. Also the 351w manifold has a 'step up' behind the distributor whereas the 302 is straight up and down.

 

Yes, there is a HO version of the 351w found in the some trucks of the 80s.
Also in the 94/95 Cobra R I believe and maybe the Lightning of the early 90s but since those vehicle were Fuel Injected, it might not be called a HO.
The HO version has a 4bbl carb/intake with a sharper camshaft profile.

The code that Fastback is referring to, can help you determine when the engine was built but that's about it.
It's usually a 4 digit number if I remember, at least through the 70s.
That number starts with a letter then a number.
The letter C would represent the 60s, D the 70s and I'm not sure if Ford kept the chronology for the 80s and up (like E,F,G etc...).
The number after that first letter would indicate the year in that decade so if your block starts with C9, it's a 1969 block (First year), a D1 would be a 1971 etc...
I don't know what the last digits mean on that code.

 

Appreciate the help, thanks.