Thanks, i will likely do the work to swap to the 411. I will work with my tuner who has experience with 98-00 BBC and likely go with whatever he suggests. At this point i don't think i am really interested in anything a COS upgrade has to offer, but i figured it may add some flexibility in the future? I will have to do some more reading thru these forums. After i do the 411 PCM, cam, headers and transmission, i likely wont be doing much else other than looking thru the maps for a little extra performance here or there and playing with the PCM inputs/outputs to control gauges/fans etc.