So i did some searching and wasn't able to find info on this...

Do you need to have a ported intake to get anything out of 58mm TB?

its a 94 383 that we just got done with. Stock heads, intake and TB....so thats why I ask

Thanks in advance

 

You're going to need to open the TB holes on the intake up for the 58mm TB because the stock holes are only 52mm in diameter. Otherwise there is a good comparison someone else just did with it.

But to directly answer your question... it should raise your HP slightly; it'd have a greater effect with an upgraded heads/cam where you can use the increased airflow more.

 

You need to have an engine making big HP with exceptional head flows "to get anything out of a 58mm throttle body", even when the intake has been bored to 58mm. Putting a 58mm TB on a 52mm intake manifold will not increase flow, and may even decrease flow due to the "sudden contraction" and the resulting turbulence and pressure loss.

 

It will run fine but as Fred indicated, it will not make the potential HP at higher RPMs unless it is machined.

NOTE: this is only relevant at high rpms. daily driving and low rpm WOT will be virtually unaffected. Put it together and get it tuned first and then later you can get it machined unless you have the time and money now.

 

wouldn't there possibly be interference with the throttle blades hitting the unported intake??

Just out of curiousity, why do you have stock heads/intake/TB on a 383???

 

thanks everyone for the info.

The reason I have stock heads because I have a budget :S