Hey Guys! I have a 94Z28 that has a 95 thru 97 opti-spark installed. It was done by a shabby shop that was referred to me by a local Chevy dealer. That Shop rebuilt my engine and was supposed to install a GM hot cam but as I found out later they did not. I had a brand new 94 optispark already on it. To make a long story short, becuase of the cam install a 95 thru 97 opti-spark had to be installed. It had no vent tube or other means of expelling the gases or moisture. It eventually failed. I have a new one and also part number gm 1255-5323 which is a vent tube. I know where this tube connects to the opti-spark, but what other components does this tube connect to? It is a double tube. A large central plastic tube with a smaller in diameter tube attached to it. What other components will I have to buy in order to convert the system to 95 thru 97 specs? By the way, that disreputable shop I mentioned earlier does not exixt any more. I guess that after many other customers complained along with myself, they closed the doors.

 

heres where mine is hooked to. u see the white plastic t with the black hoses going into and out of? thats where it gets the vacuum and on the new gm opti the vacuum goes to the top hose bib on the opti.

on the gm opti the vent hose air intake goes from the bottom vent hole to the air intake. i have a aluminum elbow so i drilled and tapped it for the hookup.

 

one thing i would and probly will change is the location of the air intake to higher up on the elbow, so it wont suck up anything that might get in the air intake. like water. lol.