These old Buick big blocks have the PCV valve at the rear of the intake. This requires a long hose to reach all the way from the back to the front, then turn 180 to plug into the front of the Q jet. Seems really stupid.
How about pulling this front tube, epoxy the hole, drill out that rear tube hole and insert the PCV tube out back?
QUESTION 1. Would there be any idle mixture problems, or lean cylinders, or any detrimental affects at all?
PCV at the rear of the carb has been done, and it can work. It has always seemed to me to be a "necessity is a mother" type of deal. You know, the crap you put up with because the carb that's being used doesn't have the PCV nipple where it belongs, and you don't want to--or can't--drill the throttle body to PUT a PCV nipple in the front. Routing the fumes to the front of the carb so they mix nicely with the incoming fuel/air mix, and therefore get distributed as evenly as possible to all eight cylinders is clearly the better plan. It is obvious that GM was willing to pay for extra vacuum hose to get the PCV fumes up front rather than in back.
"I" would never in a million years deliberately defeat the front-mounted PCV nipple just to save a foot of vacuum hose.
QUESTION 2. Would a Chrysler PCV cause an imbalance for the crankcase or the carb?
The PCV valve does not know what brand it is; or what brand of engine it's being used on. If the flow rates are approximately the same as the OEM valve (or at least the flow rates are suitable for the engine it's installed on)...it'll work fine.
Good luck getting information about flow rates or spring stiffness of PCV valves. There is NO database of specifications for PCV valves that I'm aware of. SOMEDAY, someone is going to make a billet PCV valve with replaceable orifices of various flow rates and a selection of springs, and we'll all be tuning the PCV valves like we jet carbs. Until then, all you can do is to pick the OEM PCV valve for a non- or mildly-modified engine, or pick a PCV valve from an engine of similar displacement and camshaft grind to use with a modified engine.
