I'd hate to fish out an oil-soaked wad of TP out of the cannister! But you are right- it probably would fit just fine.
I re-checked my receipt yesterday and saw the filter was $10+change.
Fred, my setup is an external metal "can" about 7 or 8" diameter, with two rubber hoses (~3/8" diameter) running to/from the engine. The can has a 7/8" bolt on top to hold on the cover. Under the cover is a little spring that the bolt threads through, and a gasket for where the lid attaches to the can. Inside is a riser tube (~1/2" diameter) that the filter assembly slides over. It reminds me of an old coffee percolator.
The filter assembly that was sold to me by NAPA looks like a coffee can, about 5" tall, with perforations all over the surface. Inside of this is what appears to be a paper element. There is a 1/2" hole top and bottom for that riser tube to feed through, and the top has a little bale that gives you something to grab to pull it off of the riser tube when it is time to change it out.
I haven't yet received my shop manuals ("they are in the mail") so I don't know if this is the stock set-up for '58. Judging by how period the rest of the engine appears, I think it either is stock, or was a typical after-market set-up from the early '60s, but that is just a guess. There are far wiser, more experienced, and older folks here that can give better information about this than me.
Bill
