Just noticed in your thread that you added nitrous to get to your 355 HP figure...
There is your power loss, fuel surge issue...
When you add nitrous, you also need to put more gas into the engine...the nitrous adds more oxygen to the fuel mix, leaning it out, unless you also put more fuel in...
This extra fuel must also be pressurized to enable it to be atomized into the airflow...
Running a standard 350 with a shot of NOS without extra fuel will kill the engine...
Any power added engine must be built to sustain the additional loads,,,forged pistons, H beam rods, steel crank, good aluminum heads, 750 Holley on medium rise manifold, cam and roller lifter set to suit NOS, roller rockers...
Fuel supply system must be 1/2 " inside diameter from pump to carb,,,3/4 ID tank to pump...aluminum tank with rear facing exit port...no 90 degree bends anywhere in fuel system...secondary higher pressure fuel pump for NOS fuel adder...
383 works well with NOS...but gets expensive fast...
Truck will also need better traction control, high stall convertor and a well built T 400, traction bars, solid bushings especially in rear. Dont forget driveshaft hoops....
Lighten the truck...no insulation or sound deadening, bucket racing seats and a roll bar with good set of seat belts,,,,
An old saying for young guns.."Speed costs money, how fast do you wan to go"...
