Vented Opti or not???

[Bad_Z28]

Looking to buy a new timing chain while putting my cam in. But everywhere I go always ask if i have the vented opti. About every parts store has told me that 1994 F-bodies had both the vented and un-vented opti (gen I and gen II). You guys have any input on this. I'm looking at getting GM performance part #12370835. It's for a vented opti spark. It's suppose to be made by Cloyes just alot cheaper.

[csmith4153]

My system doesnt ask for vented or non vented, just the p/n's for application.

Cloyes
C-3228 - Heavy Duty Timing Set; Incl. Cam Sprocket; Single Keyway Crank Sprocket; Silent Chain
9-3151 - Original True® Roller Timing Set; Incl. Cam Sprocket; 3 Keyway Crank Sprocket; w/0.5 in. Pitch Single Roller Chain

Competition Cams
3206 - High Energy; Timing Set; Chevrolet V8; 350 LT1; 1992-1994

Lunati
93094 - Plus Roller Timing Set; Single Keyway Linkbelt Chain

Maybe that will help you.

[csmith4153]

1995 shows

Cloyes
9-3151 - Original True® Roller Timing Set; Incl. Cam Sprocket; 3 Keyway Crank Sprocket; w/0.5 in. Pitch Single Roller Chain

Competition Cams
3207 - High Energy; Timing Set; Chevrolet V8; 350 LT1; 1995 And Up

Lunati
93094 - Plus Roller Timing Set; Single Keyway Linkbelt Chain

[JoeliusZ28]

I just pretty much answered this question in your PM. A 94 will NOT have a vented opti stock and i explained why this is necessary for a double roller. The vented opti will have a little hose running out of it that goes up to your intake plumbing and uses intake vacuum to draw fresh air in.

The reason people are asking if you have this is because the vented opti uses a longer dowel pin - which the double roller requires. I wouldnt say it is worth it to make the conversion for the timing set because the stock unit is sufficiently robust. However, a vented opti is a good upgrade to compliment a double roller If you do this the 9-3145 is the set you want.