Kb
These are Kenne Bell Headers. My brother and I run these headers, I have them on my 87 GN, he has them on his 88 Z/28. I ordered every downpipe known to man to fit an ATR header for a 87 GN and NONE of them fit. THEN I learned that they were Kenne Bell headers. The crossover clamp hit the bottom, the A/C box heat shield rubbed the top of every downpipe and I finally had to fab one up to work. While Alan's engine was on the engine stand, we tired bolting varius downpipes that were suppose to fit ATR headers, but also didnt work. I could only get 1 bolt to fit from the flange to the turbo housing because the downpipe was hitting the crossover pipe on hin headers too. So FAST FORWARD MOTORSPORTS in Arkansas custom made a 3 1/2 inch dp for my car. It is AWESOME! No doubt that they are awesome headers, but downpipe clearances will be an issue.
Jason