You'll have better luck finding your answers in the traxxas forum. Also, i just modded a ofna .28 force carb to fit the 4-tec 3.3 engine, this thing is gonna be a blast :P
I have the pictures up on the traxxas forums.
Avid Paintballer and Technician
Traxxas 4-tec 3.3 RWD only
Rustler VXL RPM all around geared 32/76
MaxAmps 11.1 8k LiPo