ok ill tell you this.... i have pulled my duece many times, I got my fuel pump turned about 7 or 8 times, i run a pyro, go in 2nd low ''ALWAYS'' and build up to 20 psi of boost and take off, and dont let off till the truck runs out of power, i pulled with the 9x20s too.
now 1st is too low and 3rd low is to boggy,
1 hi is to slow and 2nd hi is too boggy the 2nd low is PERFECT.
i have taken my bone stock 818 and put it strait pipe and pulled a 248, 270, and 320 today. it all matters how the sled it set up.
m818 i use low 2 as well. and hammer down. this truck grips like a mo fo. also another way of keeping all the weight on the rear axles on the 5 ton are to runs smaller tires such as the 9x20s this puts about 4000lbs more on the rear end which helps too. i dont do that becauce its not good for the t-case. it binds up, then you would need to bring equipment to swap the stuff out.
lata