I tried the Crane xr700 ignition system and just did not care for the optical trigger adjustment. So after reading several of the posts here I settled on the Pertronix unit. I have a 71 280se and the listings do not show a unit for this vehicle. At that time I was visiting the Summit Racing site. I called the customer rep who was patient and fleshing out my problem contacted the Pertronix rep who suppled us with a unit based on the ID# of the distributor. The folks at Summit were very helpful...Good Luck
MBG