Removing the smog pump

[captras]

I have a 75 vette that is all original. I would like to replace the exhaust system and get true duals, eliminating the cat. Also I have read about removing, or disconnecting, or blocking the smog pump. If I remove the pump, or just remove the belt, are there any engine/carb adjustments that must be made, or can I just drive it that way. Is there an oxygen sensor that must be removed? Lastly, will this actually make any difference on the performance end.

Thanks in advance!

 

[brusso]

I just went through the same thing on my 75. A.I.R. pump, gone along with all of its plumbing. Cat, gone. Wanted to eliminate the heat riser, but a doughnut wouldn't mate with the passenger side exhaust manifold. So I had the flapper tack welded open. As far as tuning goes, you'll here many differrent views. About all I did was set the idle mixture a little richer and set the base timing to 13 deg btdc. This ought to start something, I also left the vac advance connected to ported vaccum. I'm happy with it. I notice more response at highway speeds and no pinging.