I am trying to find who sell nos or remanufactured parts for my plymouth. I am located in california and cant find anyone. I know when i bought the car the guy said there was a place back east but i have googled it and cant find anything. What i need right now is an oil filter insert, oil pan gasket and oil pan plug and washer.

 

Have you already tried local parts stores, such as Autozone? I was able to get all of the parts you listed above for my '54 Plymouth from them. I know the engine displacement is different, but the pan gasket and filter should be the same. You can also try OldMoParts, they have everything flathead related from the 30's on up.