hpp3
HPP3 tuning seems to work for some engines, others it does not. For my car, it seemed to boost the lower rpm timing somewhat, but in the upper rpms would give me 2-3 degrees of knock retard.
What the HPP3 HAS been valuable for me is to adjust my shift points/rev limiter/shift firmness after I installed a 3500 stall TC a year ago.
I bought this pre-LS1 tuning devices, but it's all I've needed with my minimal mods.
JOEL 
