Hello again all.

I have a 1980 Plymouth Arrow 2.6 Sport. Automatic. OK.

How do I determine which automatic came in it? I think there are two different types or is there just the one?
Because of the 3:55 rear end I put in it my speedo is reading a little slow. Probably 5-7 miles slow at highway speeds. It's not too
bad in the city.

Anyone know the stock pinion number of teeth it came with before I take it off?

Thank you.