there are 4 small ports on each of the heads on my 77 350 with what looks like 3/8 tubing coming out and tieing together. I have heard this has something to do with emissions. Can i just plug these off? If I did plug them off would it have any effect on the way the car runs? I am already putting a 72 intake on to get rid of EGR valve and some other things. If anyone knows what I am talking about I would appreciate any info you would have, thanks. I will take pictures tnite and get them on too if that would help

 

They're part of the Air Injection Reactor system (smog pump). It injects air into the exhaust port to "complete" the combustion process, though in all honesty I've never heard of them on an Olds 350 unless maybe it was a California-spec engine. All 307s had them.

Plugging them will have no effect on how your engine runs and may actually run a little smoother.

 

ok, that is what I was hoping to hear. It must have been a california one then because it is an all stock 77 350 out of a cutlass. At least that is what I was told.

 

Be aware that while many people simply force brass pipe plugs into these holes, they are NOT NPT threads. They are straight threads with an inverted flare seal, just like a brake line or a fuel line into the carb. Dorman Products sells the correct steel inverted flare plugs for these ports.