Derek91z28

i had a 305 in my camaro then i put a 350 in it and put all the accesories on the 350. this motor is a 93 model with a fresh rebuild and has a roller cam. i put the 305 flywheel on it is that ok or is it throwing my timing off?? another thing is that my ecm is throwing fits. we put a scantool on it and the o2 sensor was running lean so i bought a 350 tbi and put my afpr on it. the car feels like it has a miss when you rev it up or punch it. is my computer causing this or what? it has new plugs and wires and i've visually inspected the cap and rotor i don't think any thing is wrong with the ignition system but i may be wrong. tell me what ya'll think. also since i put the 350 tbi on it and turned up the fuel pressure the plugs are a brownish and the o2 sensor is gray. what the hell should i do? and if you say i need a custom chip and a holley 670 cfm tbi then thats what everyone else says but i heard the gm injectors are the best and are able to run on higher psi than the holley ones. also i've herad the holley ones go out fairly easily. but help and comments are muchly appreciated.