I put a vacuum advance slot into an old leanburn TQ that did not have one. I had a spare TQ to use as an example for a starting point. I tell you, putting one in,in the right spot, is kind of a PITA, even for an engine that pulls good vacuum.
As much as I advocate a Vcan for streeters, I'd have to say that retrofitting a port to a carb for a low-vacuum engine,is probably going to be difficult. You will have to have the carb low speed circuits scienced out pretty good, so the butterflies are near to their final parking place. The T-ports will have to be synced up, and the idle timing will have to be really close.Then you will need to know/figure out at exactly when to start the advancing process and when to finish it, in terms of manifold vacuum,translated to throttle opening. Then cut a short slot in very nearly the exact spot it needs to be. And finally adjust the slot upwards and/or downwards to fine tune it.
Yeah, you could just drill a little hole slightly above the throttle blades and hope for the best. Then stretch that hole into a slot little by little, over time and miles,to see what happens.
If I already owned that carb, I would try it, cuz I know that the results would be worth it But I am also willing and able to put the effort into it.
Is there any chance that the manufacturer of that carb offers the same or a similar model, that does have a port? Then perhaps they could provide a template of where in the bore,to place it. Such a template would probably save a whole bunch of time and grief.
If not, I wish you every success.
As to adding a PCV port, have you given any thought to installing the port into the intake manifold plenum directly. I've seen them installed that way,into singleplanes in the back, between No's 7 and 8 runners, directly into the plenum area under the carb. I guess for a dualplane it would involve a balance tube.
