Yes the engine starts OK now. It is not too difficult to change it. You have to get the starter out of course, which is a bit of a struggle unless you have small hands. Then there is a steel cover over the drive pinion assembly which levers off. The actual drive pinion is held in with 2 circlips so you will need the appropriate pliers to remove these.
There is an excellent article at -
Repairing vintage Chrysler - Plymouth - Dodge starters - which explains it all.
If you need to buy a part,
American Car Parts and American Car Service, all things american,car,parts,service are very good and will send you one for £37 odd. Contact Wojtek at
sales@americanautoparts.co.uk.
However, I have a spare one because, after I had ordered the one from American Auto Parts, the garage that originally stripped and refurbished my starter for an extortionate fee, and did not spot the problem clutch assembly, felt so embarrassed that they gave me another one. I can let you have that for let's say £20 plus postage.