Hello, I searched for an answer for this and was not able to find one anywhere. A mechanic had taken my starter off to get replaced, long story short, im doing it now... I need help with the wiring for the solenoid. Found two posts on it here, which were contradictive of each other. Just need to know which terminals the heavy Red wire, and not as heavy black wire go on. 1980 X1/9 1.5 Marelli Unit. SHANKS!

right, the short black from the starter motor goes to the post closest to the starter motor. the big battery cable and the cable from the alternator goes to the post opposite the post to the motor if that makes sense?

Definately! Thats what I thought. Thanks for clearing that up once and for all.