Yep, the M1009 K5 Blazers are all just regular 1/2 ton Blazers suspension and axle wise. They just have the heaviest springs GM would put under a half ton Blazer and for the drivetrain they have the J-code 6.2L instead of the C-code and the TH400 instead of a TH700R4 or SM465.

I'd bet the axles haven't been touched and he's probably trying to deflect people's thoughts away from, "damn, 4.56's are LOW...bet it only goes 55mph!" and then being pushed away.
