Has anyone installed a Stack Raciing 70mm throttle body on their 4.6 or know anything about their products? It is a new product carried by American Muscle. The price looks right if they are any good.
I just now installed the Professional Products 70mm TB and 75mm plenum. No experience with your brand, but I got a noticeably better throttle response and maybe 8 to 10 hp (still need a dyno verification on that.) Definitely recommended imo.
Bigger throttlebodies are a complete waste until you are well over 300hp. It simply isn't a restriction compared to the heads or exhaust. Same goes for everything else in the inlet tract.
The "better throttle response" is simply physics. A bigger TB is going to allow more air to pass at a given pedal position. More air is more power, but as you get close to wot you lose velocity, which can actually cost you torque. So yeah it feels stronger, However it isn't going to give you any more power at stock levels. People that "see" a power increase nearly alway have significant mods already, or had a tune applied at the same time. Most of the time its a tune that actually is the source of the boost in power.
I agree with MIDNIGHT2V. An engine is essentially an airpump. You have to be able to get the air out you put in. I was just curious about the Stack Racing TB. I had gotten an Email from American Muscle and didn't recognize the brand.