Need help before something goes wrong

[Walts_restoration]

Alright guys, my 86 k5 (yeah, not the blazer forum but they are the same as the trucks for what i'm doing) Originally came equipped with the 305 4v, i believe they had the one piece rear mains (not for sure) and im swapping to a 1975 k5's 350, witch is a two piece rear main. What Flywheel do i use? Does anything special have to be done to make sure it hooks up right?

Im also going to be using a holley 650dp on top, a little swap meet find that im rebuilding. Do i have to buy any special brackets for the kick down on the 700r4? i thought i read somewhere that if the cable wasn't adjusted perfectly it would cause the transmission to fail?

And, finally, would it hurt the tranny because i am not using the computer controlled carb and other emission bull? thanks