hey everybody, I just had true dual exhaust put on my all stock 86 Salon, with 307. Just has regular stock type mufflers, no converter. Sounds just fine, but now I have a slight pinging under light acceleration. This was not present at all before, and noticed it right away on the way home from the muffler shop. After some research, I have decided that the reduced backpressure has affected the way the egr works. It's a positive backpressure type, and depends on enough backpressure to close it's vacuum bleed internally, which evidently is not enough since the exhaust work. My question is, which Oldsmobiles used a regular ported type egr? I think if I use one of those, it might solve my problem. Just a regular type valve that moves whenever vacuum is applied, (with no bleed hole). I think I read somewhere maybe a 1976 Cutlass 350 application? Sorry for the long post. Thanks in advance for any ideas.
