My 69 still has the points type distributor and I would like to change it over to an HEI distributor. Do I have to buy a complete HEI distributor or can I just install the HEI cap and rotor? If I have to change the complete distributor assembly who makes a drop in HEI unit, where can I get one and how much do they run? I'm still new to the 1st gen and I appreciate all of your suggestions and help, thanks fellas.