Threaded barrel

[sheepherder]

Originally Posted by Ron Wood

That coarse thread and heavy shoulder are made for attaching an automotive oil filter.

OK, now I remember that thread! But for the oil filter, you still need an approximately 3 1/2" disk between the filter and the barrel to block off the holes for the oil return.

And as a suppressor, the action needs to be locked. If not, sound will still escape from the opened action.

Chevy oil filters are best. Chevy made at least three length filters for the SBC, the longest being ~8" long/2-quart, for the light truck [AC Delco PF932]. More absorption material for suppressing.

Chevy thread is 13/16" x 16tpi.