i have a 86 irock 305 tpi im switching to a 350 i built with aluminum heads iv herd so far i would have to up grade the injectors but the main question is is it posible to use a lower vac cam with the tpi set up or should i just change it to carb

If you want to retain the TPI, you'll need a new ESC module, knock sensor, injectors, and a new tune on the computer.

What cam do you have in the new 350?

i dont have a cam in it at the moment but i def wanna go bigger than stock was looking at the 12-242-2 comp extremem energy cam

With the tpi I would go a little wider on the LSA, and look into the comp extreme fuel injection cams. One comperable would be the 12-366-4. About the same duration, gobs more lift, and a wider LSA.

http://www.compcams.com/Cam_Specs/Ca...?csid=121&sb=2