Hi , I am have a very good question, I have an 80 chevy malibu that came with a 305 and i have recently replaced it with a 350 out of a friends 80 chevy half ton truck. The problem is that my old mechanic put my 305 distributor on this 350 and it seems to not be correct . At the local autoparts i cheaked both distributors and they come out to be different parts for the malibu 305 and the truck 350 , But they look very similar and cant tell any difference. Please help !

 

The only thing that may be different that I can think off would be the advance curve.Different weights and or springs on the centrifugal advance and a different vacuum advance.Should work ok.You can change them to suit your needs if you wish.I would leave it alone personally.

 

Is it running OK?

 

Absolutely No difference, other than the advance components as Davo mentioned. Hence the different part number. All Small Block Chevy distributors or that era were the same.
Billy