So I'm doing the ignition conversion, swapping the '85-style for the '87-style, I have the conversion harness from Caspers, and I'm wondering about the coil pack and ignition module. Can I use the coil pack and ignition module from a late model 3800? Are these compatible with the '87-style ignition? If not, Full Throttle appears to have a coil pack for $70, is this a good unit?