I need to replace the wornout front coil springs on my 67 bird. My motor is a 428 out of a 69 Grand Prix with an aluminum (Edelbrock) intake and a Holley carb and no AC or smog gear. Should I use the springs for a '67 400 w/out AC, a '67 400 w/AC, or go the custom route? Is a '69 428 substantially heavier than a '67 400? Is there a '67 428 spring?
