How much plug wire clearance do you have on your c-1 ? What brand heads,and headers do you use? 15/8 or 13/4 tubes? Straight or angle plugs heads?

 

Not that the generation should make a difference, my C3 uses an early version of the Chevrolet angle plug head, with Hooker sidemount headers. The wires run alongside the valve covers and then drop down to the plugs with at least a 1/2" of clearance using Moroso wires with 90 degree boots..

 

I should have mentioned it was a small block and the headers were hooker super competition 13/4” tubes. In the past I had GM angle plug heads , the center plugs were close but doable. The header manufacture said not to be used with angel plug heads.