My Indy advised against buying an early 129, as there were many updates made throughout the line through the mid 90's, and the earlier parts are not available. You will be forced to buy the upgraded parts at a considerable expense over the original parts as designed. He recommended buying a later version, or if an earlier version, on on which the parts had already been upgraded.
Regards, Rory Morrison Oroville, WA 1985 300SD 1982 300TD