pic of the cap
Cool forum. I am joining because i plan to do some serious tuneup on my 1988 b350 (5.9L 4bbl V8). Ignition system comes first. And my first question: how do you know if your distributor shaft is 12.5mm or 16mm and why are there "OE" parts for both sizes? I hope somebody knows!

 

that's an ironhead 318----good motor

 

Thanks. I remotely could tell this was an awesome buy. Is 318 the cid? If so it's actually the 360. Know anything about distributor components for these? I'm finding OE parts for a 12.5" or 16" distro shaft and have no clue how both can be the right size unless it is to accomodate replaceable parts like rotors, etc. Probably will just roll to the store and compare tomorrow. But if anyone knows, please share!