People put way too much into this MAF conversion idea. The map works just fine until you go to an extreme cam that drops vacuum below a useable level. These are the types of came used on fuelers and drag cars. If the vacuum is that low on a street truck you will loose brake booster function, EGR and anything else that runs on vacuum. But with heads headers cams valves etc you still run around 20" at idle and 0 at wot ant the MAP reads that just fine. MAF computations are more accurate but map still works. Many new cars with forced induction or direct injection rely on map only.

 

Change out your gears to 4.10 or 4.56, best thing you can do to a 302. The 302's power is all in the high RPM's which means it has little torque. It will really wake up your truck.