this is just an idea right now.. but if i were to make a custom intake manifold for my lt1 would it be a bad idea to place the MAF behind the throttle body? the only bad thing i can think of is the heat. but also wouldn't it give better readings because the amount of air it will sense will be more accurate compared to the cooler denser air it reads before making it to the hot manifold?

 

The sensor is no more accurate whether it is reading hot air, cold air, dense air or thin air.... it uses the wires to heat the small sample of air that is in close proximity to the wires, and uses the power consumption used for heating the wires to calculate the mass air flow. There is internal temperature measurement within the MAF... so hot, cold, pressure, vacuum..... doesn't matter, the MAF can measure the mass air flow with equal accuracy.

What upsets the MAF sensor is turbulence. It needs SMOOTH flow past the wires, with the velocity of the air across the full cross-section of the sensor being as uniform as possible. And there is where the idea of locating the MAF after the throttle body falls apart. There is way too much turbulence created by the variable position of the throttle blade.

An MAF sensor is simply a "hot wire anemometer"... and when designing instrument systems for high accuracy, you would want at least 10X the diameter of the meter in straight pipe before the meter.... or, if you have a 3" MAF meter, you would ideally have at least 30" of straight pipe before the meter..... not a "constriction" like a throttle blade (or two blades). Of course its hard to fit a 30" run of straight pipe in front of the MAF, so they use a flow distribution device ("screen") to help provide a uniform flow velocity across the full area of the meter.

You also want to isolate the meter from the pulse flow of the intake manifold. A large plenum on top of the manifold should accomplish this, but the further away from the plenum the meter sits, the easier job it is going to have accurately measuring the flow.