400mphpc

Hey guys,
Looking for suggestions. I have a 1976, Cutlass w/350, 4BBL Rochester, 49K orig miles. The car sat in a garage since 1985 until I purchased it this past spring. I've been tweaking the engine most of the summer & trying to get the final quirks out of it. I rebuilt the carb, replaced the ignition wires, plugs, Dist cap, rotor button, coil, ignition module & vacuum lines. Would you guys recommend blocking off the EGR valve to improve vacuum to the carb or leave it connected.

Thanks in advance for the help,
Chris

joe_padavano

If it's functioning properly, the EGR valve should only open at part throttle, so it really has no effect on WOT performance. Arguably, it can even improve part throttle gas mileage, but I'm not completely convinced. The problem with the mid-70s cars is that the EGR was operated by a series of thermo-vacuum switches and ported carb vacuum. If these (or the connecting vacuum hoses) are bad or mis-connected, the EGR may not open at the right time. Newer cars (including the 307) control the EGR more precisely using the computer.

400mphpc

Thanks Joe,
I figure I'll play with it both ways & see what happens. Since it's not WOT all the time, I would prefer the extra MPG if it truly does help. I have not replaced the thermal port switches as they seem to be functioning ok.