Re: Chevy vortec performance
I have a 98 Z-71
good stuff for me = Started with Volant Intake and Magnaflow Catback exhaust, slight but noticeable increase, dual flex-a-lite electric fans very noticeable increase in mileage around town, JET module nice increase(could feel the difference, i will test on dyno before and after soon) and loved the harder shift so much i installed one of there Powershift modules.
not impressive=TB spacer from poweraid(whistle sound and no increase, made real tight fit for intake), Performance Pulleys no seat of pants increase, slight increase(temp could have been a factor) on dyno but not enough to jeopardize my charging system.
my two cents