I've read this on the LS1 car stuff on this site, some of the car guys have turned their ported maf's around and have gotten better ATAP numbers. I remember some guys actually dynoed his Z28, stock maf, ported maf normal and ported maf backwards. He claimed he got the most HP & TQ with the ported maf backwards!? They started trying this because the ported maf's were causing their cars to run lean. What you think, work for a GMS maf on our trucks?
Jim

 

If I recall correctly, there was a guy not long ago that accendently installed his backwards when he installed his K&N kit and it ran like crap. But with some mods it may run better. Just make sure you have Atap or some sort of scanner so you can tell us for sure if you try it.