So I know the throttle body is just a valve for the air and I've seen the stock 55 or 56mm throttle body be fine with around 300whp, but is there a limit? I would assume the throttle body would need to be enlarged if you try to cram more air in. Does anyone have a good way to measure the airflow into the engine and how restrictive a smaller throttle body would be? I know you can just go big, but then you would lose out on low-end power because the opening is too large. I'm mainly trying to find the perfect size for any setup. I currently have an OBD0 DOHC ZC intake manifold, so my only options are stock 55mm or 58mm B18A throttle body.