Skokie, You'll need the distributor, cap and sparkplug wires to match the cap. Not to confuse you but there is also an early version of the HEI that does not have the coil in the cap, still the cap is going to be about twice the diameter of the original. Have fun.

Regards,
Larry
63 C20 daily driver

I don't own a vehicle that isn't old enough to drink.