I have attempted to solve this backfire issue. Changed sensors, had a garage index the distributor, nothing has worked! I am done with this Renix system. I have a 0630 head, 1995 exhaust manifold, and 1999 inlet manifold. I am thinking about modifying the inlet manifold to accept the Sniper EFI 2 barrel, Sniper Management, and Distributor. My thinking is to strip our all the Renix and run with the Sniper EFI. What challenges will I have to face?