Originally Posted by BigEd_72455

Dead thread reborn... but here is the info I found:
in factory format (no porting or filling) we flowed:
the 1996-2004 4.3/5.0/5.7/7.4L (vortec) @ 780cfm
the 1999-2002 4.8/5.3/6.0L (cable version) @ 759cfm
the 2001-2002 8.1L (fly-by-wire) @ 795cfm
the 2003-2004 4.8/5.3/6.0/8.1L (fly-by-wire) @ 792cfm
the 1998-2002 5.7L (f-body cable version) @ 766cfm
the 1999-2002 5.7L (y-body fly-by-wire) @ 790cfm
the 2003-2004 5.7L (y-body fly-by-wire) @ 800cfm
all tested on a SF-1020 Flow-bench @ 28" H2O
*note* all versions with an idle air control couldnt break over 780cfm
a 496 (8.1) @ 6000rpm requires 870cfm air-flow @ 4" hg @ sea level
a 350 (5.7) @ 7000rpm requires 725cfm air-flow @ 4" hg @ sea level

Originally Posted by Fast355

I can tell you right now the 7.4L vortec throttle body is not the same as a 4.3 or small block V8 unit. It is larger all the way through unlike the smaller V8.