Okay so I have a 74 260z that im looking to get as much torque and acceleration as I can. I have the basic 2.6 with dual webers on it with headers and all the emission junk removed. Ive replaced the starter, water pump, radiator fan clutch, upgraded the 4 speed to a 5 speed tranny replaced the brake booster, master cylinder, the clutch master and slave cylinder. What I have left to do is get the alternator rebuilt or replaced, replace the coil, get the headlight harness Dave makes, and replace the gas cap (the one I have doesn't seal and when i take left turns with a full tank of gas i loss my fuel) also I kinda want to upgrade to a stage 2 cam and redo the differential to get some serious torque... Unfortunately I dont know what I already have... havent checked but what I would like to know is what would upgrading the cam and changing the gear ratio do for me? and how or what do i need to do or get to achieve the most get up and go of the line?

Most cam grinds move the powerband up the RPM range unless its a very mild grind, your best bet is to get a 5 speed from an 83 280zx and a 3.7 or 3.9 rear end

Your fuel might be coming from a cracked rubber filler tube.