Some refer to that distributer as the Two-Bolt distributer or "crab" as mentioned. As noted timing not adjustable. Recommend NOT fooling around with the vacumm assembly on top of the distributor unless you have the right equipment and experience. If th evacumm piston is proper fit and condition should be okay. Point setting specified is "aveage" and workable but setting them with a dwelll meter is better. I get my distributors, coils, carb's and pumps as rebuilt's from Charlie S He tests every item on a shop engine before releasing them. I keep spare distributor, carb and pump in my trunk. Given my experience, condensor's seem to cause more problems. NAPA carries good condensor and point replacements. Re air filters, my '47 is not a performance engine. I use the original oill-filled air cleaner and adjust the carb idle screws using a vacumm gauge.