im currently rebuilding an 85 corvette (i know, not a thirdgen, but i have a thirdgen too and quite frankly the people on this site are way better than at corvette forum). anywho, im having some vacuum line problems that i need to have fixed by this weekend cuz i have a car show to go to. anywho, theres a line that splits under two underneath the plenum and the splitter is pretty well trashed, so no vacuum is getting anywhere. would it work, if even as a temporary fix, to use a capped off vacuum port i found on the emisions crap up front and just run a seperate line (the split by the way, goes to the fuel pressure regulator and the side of the plenum) or would running them out of order mess things up real bad? thanks for any help, please i need it asap cuz the show is this weekend!

 

It should work fine, vacuum is vacuum. The only real difference is manifold or ported vacuum. TPI engines only have one "ported" vacuum line, it goes from the throttle body to the breather on the passenger valve cover. Even it is really just an air source for the PCV system. Manifold vacuum is behind the throttle blades (or above the carb blades), it decreases with RPM. Ported vacuum is in front of the throttle blades, it goes up with RPM (like needed for distributor vacuum advance on older cars).

 

thanks for the help! i actually feel kinda dumb because i realized instead of trying to find a y connector i couldve just used a t connector and bent the lines different.... which is what i did. car runs great now. thanks for the info, that was actually really interesting and i had no idea there was a difference.