'64 Dart, '73 Scamp. What's the difference???
The Summit one is probably the same $50 rebuilt one I bought on ebay with a markup to their pockets. I suggest buying 2 from the junkyard for $10 ea and carry the spare in your trunk. That will weigh the same total as the original (w/ better weight distribution) and give you 100% reliability since you have backup. Just carry the wrenches needed to swap. I can't do this in my 273 because removing even a mini-starter is a #!@$, but almost a fun job in a slant six.