68 C60 Question (maybe Joe or Duke)

[Dale C.]

I am having a little trouble understanding the plumbing for the vacuum advance lines on a 68 L36 with C60. I think the AIM plumbs the non A/C 327 and 390 BB pretty much the same. The steel tubing with the rubber ends, one end at the carb and the other at the distributor vacuum advance control. If you look at the AIM (C60, C8) the intake manifold vacuum tee is split with one branch going to the distributor controller and the other running off to supply vacuum, I think. The line to the carb is omitted and a cap is placed on the carb port. Is this correct and is this why the carb idle solenoid is added? My car is set up like non A/C L36 with the line from carb to distributor and a single intake tee running vacuum. I put on the breakerless ignition. Do I need to add the split tee at the intake manifold and re-route vacuum as shown, pull the carb/Distrib line, and then add that 3940920 cap? This is the biggie, where would one find that puppy, or what could one use to cap the carb? Nothing is simple with a 68 BB A/C. I think I understand, the vacuum pick up off base of carb was just in the way on A/C cars with that idle solenoid so they changed the vacuum to the intake tee, maybe.
Thanks
Dale