id do a zex kit over a nos kit and definitely over a nx kit, but i would not run a wet shot unless ur doing something with forced induction on a n/a setup definitely go either dry or direct port, direct port involves alot more work but will allow for larger shots later on down the line if ur planning on stepping up and building the bottom end, i personally run a zex dry kit part number 82011
http://www.genxmuscle.com/store/82011
and have not had any issues, i bought an after market msd ignition system and use zex plugs but thats it. for that larger engine 75 shot shouldnt be a problem for occasional fun but if u plan on using it more often id suggest a 50 shot for reliability issues, if ur not building the bottom with forged parts or building ur fuel system up. with a 75 id suggest a beefier fuel system and retarding the timing a good amount.