Here's my plans

I have a 97 K-1500 z71 with a 350 in it and i wanna get it up to around 375HP. rite now all i have is true dual flowmaster exhuast and i estimate my hp now to be 281. I want to buy a GMS enclosed cold air intake kit, a GMS mass air flow sensor, BBK high flow throttle body, AIRAID throttle body spacer, JET under-drive power pulleys, Gibson headers, and possibly a GM max micro tuner. by my estimates this should put me in the 375-400hp range. anyone with these products on thier trucks please tell me how well it works as well as any effects it may have on the truck other wise(gas mileage, driveability). THANKS!

I don't want to burst your bubble or anything buddy, but a 1997 350 has 255 hp from factory, and true dual exhaust, no matter what anyone says, won't add 26 horsepower. With the exhaust, you MIGHT have picked up 3-5 hp. I have Flowmasters as well (still have the converter, and only have the one muffler with one inlet and two outlets) and I noticed a pretty good gain in low end power. I may have a couple extra horses, but probably not, lol! 400 horsepower is hard to get. I dont think bolt on parts or exhaust will do it for ya. You're gonna have to change the cam and have some head work done to get to 400. Now with the programmer and all of that, you probably will get to 300, but definetly not 400.

The race car I have pictured has a 400 small block bored .030 (406), 12.5:1 pistons, .636 roller cam, 5.7 in. steel rods, steel crank-balanced, 2.05/1.60 valves, race ready holley carb, etc (its modded pretty heavily) and the shop that re-built it this winter estimated 550-600 hp. My point is its hard to get big horsepower, even with internal mods, much less bolt on parts.