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kevinr1970 · 03-05-2015, 05:44 PM

Manifold

But... there is this note:
"This manifold is primarily intended for use with Vortec heads on pre-1996 engine blocks. Blocks manufactured in 1995 or earlier have thermostat bypass passage from the block directly to the water pump. If manifold is used on 1996 and later engines (which do not have the bypass in the block), you must run a coolant bypass line from the manifold to the 5/8" hose nipple on the water pump (passenger’s side). Suggested routing is from the 3/8 NPSF boss on manifold to the water pump."
"These Vortec manifolds with TBI from Chevrolet Performance are designed for maximum horsepower with throttle body fuel injection and EGR usage. These manifolds will fit all Vortec-designed cylinder heads."

Might be cheaper to find a vortec 4bl manifold and use a TBI adapter?
1-11/16” bore TBI adapter
2" adapter
2-1/8" adapter

03-05-2015, 05:44 PM	#4
kevinr1970 Senior Member Join Date: Aug 2004 Location: Everett, WA Posts: 2,316	Re: 96-99 5.7 vortec swap Manifold But... there is this note: "This manifold is primarily intended for use with Vortec heads on pre-1996 engine blocks. Blocks manufactured in 1995 or earlier have thermostat bypass passage from the block directly to the water pump. If manifold is used on 1996 and later engines (which do not have the bypass in the block), you must run a coolant bypass line from the manifold to the 5/8" hose nipple on the water pump (passenger’s side). Suggested routing is from the 3/8 NPSF boss on manifold to the water pump." "These Vortec manifolds with TBI from Chevrolet Performance are designed for maximum horsepower with throttle body fuel injection and EGR usage. These manifolds will fit all Vortec-designed cylinder heads." Might be cheaper to find a vortec 4bl manifold and use a TBI adapter? 1-11/16” bore TBI adapter 2" adapter 2-1/8" adapter __________________ 2009 Honda Fit CfC (bsf 44.9 mpg) 2000 Tahoe Limited 1991 GMC CrewCab Dually 2wd, will end up swb, not dually and replace CCswb below 1991 GMC CrewCab Dually 4x4, just going to fix things up for now 1982/1989 K5/GMC Jimmy 2wd 1987 GMC 1/2 ton swb 2wd Crew (sold) Last edited by kevinr1970; 03-05-2015 at 06:02 PM.