OK...so I pick up this '56 3600 with what appears to be a Pontiac 347 V8 (thanks Luke). It runs but a little rough and is very cold blooded. I thought I'd start by checking the spark plugs. WT*?? They don't have a traditional electrode and are imprinted with "Leonards Oil Firing" on the insulator. What's up with that? Do they cross to a more modern plug?
