Actually, the experience I have heard about most with straight methanol injection is BOOM! New window in the block. Especially with your 2002, which has brittle PMR rods on it. What are you doing with your truck that requires more power? That has a lot to do with what a "safe" increase in power might be.
That said, a lot of guys run a 50/50 mix of water and methanol, and it seems to be pretty safe. It is all a matter of cylinder pressures. Injecting a fuel into the intake of a photo-ignition engine can result in HUGE cylinder pressure increases, because volatile fuels, such as propane and methanol, will typically photo-ignite at ratios in the range of 9 to 12 to one. Your diesel goes to about 18. This means that an intake-injected fuel pops when the piston is only about halfway up, which means that the combination of expanding, burning gasses, and the reduction in the area the gasses have to expand (due to the piston moving up in the cylinder) combine to create very high cylinder pressures. The result can be fractured rods, bent rods, popped headgaskets, and other nasty little things.
Two things can mitigate this. First, mix your methanol with water, in any ratio you want, making sure that there is never any more than 50% methanol in the mix to be totally safe. You can go 25/75, 30/70, etc, as long as there is never any more than 50% meth, and you will be good. How does this help? Well, the water quenches the burn to an extent, and helps to prevent the meth from photo-detonating so early, which will reduce CPs. Also, the water acts like a chemcial intercooler, and will help keep your EGTs down. Adding meth will help your EGTs skyrocket, so water helps compensate for this. When you are towing long distances, and don't need power, you can even put in 100% water, and just use it to keep your engine running cool.
Second, reduce the amount of meth you inject. Logically, less fuel means less CP's, and the addition of even a small amount of meth should increase your power by a pretty good margin. The reason for this is because the early detonation of the meth means that your diesel will be injected into a fireball instead of the top of your piston. This means that it burns much more efficiently, giving quite a bit more power, and purportedly more fuel economy, too.
Give us some more info on what Banks stuff you have. Advanced timing also creates higher CPs. If your banks stuff advances timing a whole bunch (which it probably does) then this will compound your CP problem. Your PMR rods just can't take a whole heck of a lot of abuse. You put down 400 HP and they are about ready to implode....
Sounds like friggin rocket fuel to me!!!
