Right now I'm going to be putting in my new upper intake to gain more HP and allow for more total HP and new valve covers. While I'm replacing it im thinking of putting in another throttle body but not sure what size to get. Eventually, not this year, I'm going to put either a turbo or supercharger in it. So all that being said what size? 65mm?? 70mm?? 75mm!??? I know I don't have to do it now, but I figured while I had it apart from the upper intake i'd replace it. Lemme know what you guys think.

 

what kind of intake? whats the rest of your combo look like? we need more information than what youve given us.

 

+1^^^

 

65mm or 70mm will work well. It really does not matter between the two. You won't lose/gain any power between the two

 

Depending on the COMBINATION, it may be more fruitful to go even larger. Do you know what his combination is?

 

No, I do not. However, unless he's running a 347 stroker with turbo or supercharger, a 65mm or 70 will suffice. Heck the stock throttle body can easily support 300rwhp, before it starts to hamper flow. There are people running 65mm TB's pumping out 450-500rwhp. It seems the OP is pretty mildly modified(stock heads and cam), so it's safe to assume that either TB's will work fine.

 

whats the opening size on the upper intake your putting on

 

If he plans on spinning rpm with this engine a larger throttle body maybe needed. Combination and goal will dictate what is needed to make the determination. Let me guess, by your theory a 75mm is too large for a 302 or a +900cfm carb is too large for a 289.

 

This does not matter in most cases, the plenum can be opened up. Easily I might add.

 

I am not saying that at all. But it sounds like you are saying a 65mm would be too small for a 302. I have a 70mm TB. Do you think that it is too small for my boosted combination?If we wan to start this argument between which Throttle body works best, then lets just settle on a 70mm, since it's right in the middle and call it a day.