I'm working on a SBF 289 w/ 4 Weber 48 IDA's. There are only 2 vacuum ports drilled into the two rear intake ports (cylinders 4 & 8) to provide vacuum to the trans vacuum modulator. Curiously enough - no PCV! IMO, this really ought to have a PCV! I was going to add on a vacuum canister, plumb it to the intake, and then have 2 outputs, one to the PCV and one to the trans (no power brakes). Anyone see a problem with this? Only thing I could think is that I might have to remove the check valve to keep the trans from shifting weird. Right now, I have to back off the throttle to build up some vacuum so it'll upshift. Thoughts? Experience? Thanks!
PCV systems are controlled vacuum leaks. Air carries the by pass gases into the intake. If you plumb it into just one cylinder, I'd be afraid it would lean out that cylinder. All the factory PCV systems that I'm aware of are plumbed to the base of the carb so that the extra air gets distributed to all the cylinders. I plumbed my 2x2 intake with a yoke between both carb. bases to try to equalize the additional air. Without a central plenum it could be tough using 4 carbs. If there is a balance passage cast into the intake between all 4 carbs, I'd plumb it to the center of that passage.
Right on. There's no common plenum on a weber manifold - one veturi per cylinder! Inglese says do without a PCV - just didn't sound like a good idea to me. If it was my car, I'd take the maniold and tap a very small port into each runner and then tie them into a common "manifold". I suppose I could fab some sort of manifold (or can/reservior) to hold more so the trans would act a bit more normal... still don't think I'll build up much vacuum very quickly with only 2 ports contributing. More input welcome...
I've got similar problem. My Chevy runs like shit with out PVC. I have one of Pierce Manifolds SBC Manifold with two 44 IDF Carbs.. I think Carb spacers can be drilled and tapped for both PVC and Vacume for the Auto trans. I need a Bell crank with a provision for Trans kickdown.