do you mean to say a dizzy cap (as in burnt out points where the rotor sparks?)
my bro has fitted a 4age series single coil cap to the GZ dizzy and works fine. if thats what you meant - not entirely sure wether you mean the distributor cap or rotor assembly. (thats single coil BTW)
cost him just short of 30 bucks.
if what i told is right the dizzy cap and gaskets are identical btwn 4age and gze (single coil) donks.
(ie if you use GZE head gaskets on ge thats fine.... as an example. prolly not a good idea to go the reverse tho)