Has anyone used one of these adapters? I was wondering if it just fits down in tone original canister so it still looks stock?

 

What do you mean so it still looks stock?? Answer no it wont. Its going
to look spin on. Adaptors can be obtained from Napa, they will fit all
Y blocks make sure it is installed with the hole stamped "top" on the
top. My father hated those canisters usually ending up getting soaked
back when they were new.

 

If you are talking about a stock filter setup for a '51, it has a completely different type of filter system. It is not a full-flow filter like modern engines. The flow thru it is about 1/10 of what a full-flow sees, but the filter media is finer. There is a restrictor in the plumbing to the stock filter and if it is removed, you'll have almost no pressure to the bearings and things go bad pretty quickly.

 

1957: Ford introduced the 'Spin-On' oil filter/adapter for 215/223 I-6's and 239/256/272/292/312 Y blocks, available at the parts counter as a kit (B7A-6882-A). Could be retrofitted to earlier years.

The Spin-On filter was originally B7A-6731-A, was replaced in 1961 by C1AZ-6731-A (Auto-Lite FL-1), then in 1973 by Motorcraft FL-1A

Same FL-1A filter fits ALL FoMoCo I-6's and V8's well into the 1990's...except 1975/78 Mustang II 302. Ford 'shoehorned' the 302 into the engine compartment.

These cars use FL-300 .. as FL-1A was too long, hit the engine crossmember. Mustang II is basically a reskinned Pinto.

 

Don't know what engine he's got, but a '51 would be a flatmotor of of some flavor. No full flow option short of doing a bunch of machine work.