I have used 2 of them also. One on a big ol Craftman 5 speed rear tine tiller. The othe was on a front tine Bolens tiller. Just make sure you get the right shaft size for the pullys. Both were direct bolt in.
http://license-renewal.org/new/?&source=CCN-CD312-MSN-DL-DMV-Renew-Broad-J1-dmv%20gov&keyword=dmv%20gov&head=DMV+License+Renewal&sub=Provider+of+DMV+License+Renewal+Service
They can give you the exact figure you are looking for.
I zap them with my Miller 210. It wont make them new again. But it makes them last a little longer. I use leads and zap the leads so that the battery doesent get all shlagged up with the wire.
Bunch of Youtube vids on the subject.