Most people doing the e-fan conversion use a Ford Taurus 3.8 2spd fan or LT1/LS1 f-body dual fans. The taurus fan will fit perfictly. You will either need to tap into the stock temp sensor or buy adjustable temp probes to trigger the fan. You could also use a fan controller like one from SPAL. Relays depend on what fan you want to use. It may not be a bad idea to upgrade your alternator to reduce the amp draw and maximize the hp gain. A cheap way to do that would be the GM AD244 alternator.
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2000 Chevy Blazer ZR2
Performance Mods: Numerous
Suspension Mods: Some, but not enough
Exterior Mods: Just Right
1987 Buick Turbo T Dark Red
Low 11 sec sleeper
.030 4.1 block, PT6262E, & other odds and ends....
My Cardomain