Vacuum Advance Canisters

[BMERDOC]

I've been studying every aspect of my truck to better understand it and increase its performance. The engine is a boat anchor integral headed 250 out of a '78 Nova/Camaro. I've got it running really good. I've been studying ignition timing hoping to squeaze any extra I can get out of it. It has an HEI in it and I'd like to get a re-curve kit to change out the springs. My research indicates that if I add the springs for faster advance I need to change out the vacuum advance because the stocker adds too much advance sooo...my question is this: Will the V8 HEI vacuum canisters physically bolt into the big cap/external coiled inline 6 distributor?
I do not have all my info yet. I know that I have set it for 8* initial but I dont yet know what "all in" timing is at and at what RPM or what timing is with the vacuum canister plugged in. I'll get that info later if I find that a tuneable vacuum canister is available for me.