Not quite the situation there pal. Both 5 speeds and auto's are 235 HP configured engines. Only 6-speed manuals have the 245HP rating. The auto isn't rated for anymore then 235hp with the rated load capacity. Not looking to be cokcy, but I don't want to see misleading information.

 

so bigger injectors are gonna give me more power right? is it harder on my tranmission

 

Yes, you will get more power. You will also have higher EGT's and more smoke, as the air quantity will be the same. It will definitely effect the longevity of your transmission.The auto's in these trucks are not very strong at all. I performance torque converter and valve body is a good start to keep it all together.

 

Ok I was told that was the reason but thank you RAWilliams for correcting me.

 

the reason lies in the actual injection pump as the ho pump has a larger cam in it, but smaller plungers and barrels(can't think of the correct name for them in a vp).

 

Higher compression ratio too.

OP you will need an aftermarket lift pump like an AirDog or Fass. Otherwise its $1000 for a new injection pump and the lift pump on top of it. The search function is really gonna be your best friend here.