98 vortec 454 and 400 turbo problems

[alaska]

I am building a 98 chevy monster tour truck. I am using the 98 chevy 1 ton crew cab and the vortec 454 that came with the cab. I am putting it on a 2.5 ton frame.I want to hook it up to a turbo 400 with a 205 because I will be submerging it in water a lot. Is there a wiring harness that will help me make everything run right or will I be able to use the original, what problems with the trucks computers am I going to run into. I am mostly concerned about getting rid of the speed senser and of course all the tranny electronics Any info would also be greatly appreciated.