Looking for info on a Delco ATH chip from a 86 GN. I can't see the number due to the plastic carrier. Google didn't help. So my 86 is stock except for a few things: brakes, rear seat brace, fuel hot wire kit. The car is in very good shape for stock (and I would like to keep it that way as much is practical). So I had to replace the exhaust due to age, and went with a Pypes with a low flow cat. Now I get ridiculous knock and newly installed Scanmaster shows lean. I know the next step will be a fuel pump and guage. What I am curious about is how strong this car is off the line and in 2nd. It pulls Hard and I am only part throttle to prevent knock. I love the acceleration. The stock turbo spools fast. Any information or advice is appreciated.