astronut1885
Founding Member
Guys- it's all about air velocity and air volume. Imagine a 2 liter bottle of coke. Pour it down a narrow hose. Not much gets through at once, but it moves fast because of the pressure behind it. That's a stock TB. Now go to a huge chunk of PVC. Pour it through. Yeah, it all gets through, but not as fast, and it's all over the place, very turbulent. That's a TB that's too big for the intake capacity. Now get a middle sized pipe. Pour it through. Now it moves fast, but it's also moving alot of quantity, which is the perfect situation. You want a throttle body that will supply enough air, but not too much so that it stalls and you loose all your torque. I say a 70mm is more than enough for a 302-306-308 N/A motor, unless it's really extreme, then a 75. I'll be getting a 70 for my combo.