ICM – ignition control module

I have a 76 Cordoba -400cid 2 barrel. The ICM - Ignition Control Module or ECM listed for that car is 8A1 from Rock Auto / AIRTEX. The website picture shows 5 pins for the plug. My old (bad) one has 5 pins. They sent me one with 4 pins. I cannot find a 5 pin module anywhere. I have looked at NAPA, Year One, Summit, Parts Geek and Rock Auto. I dont believe anyone makes it. The 5 pin is used in conjunction with a 4 prong ballast. at low idle- one set of prongs is used and at high speed the other set is used. I am the only one needing a 5 pin ?
I am wondering if the 4 pin could be used with some alterations. THANX

Ed Scotch
Author: scotch