I have 94 burb bb 454, aluminum intake unheated, upped fuel pressure, ported heads, headers and .500 lift cam. It came with 6395 and that is what I use but have swapped 7427 in and no difference. I did a lot of tuning in the beginning but haven’t burnt a chip in two years. It is a daily driver and runs great. I run in open loop with auto iat correction.