i have a 52mm right now. if i bought a 58mm tb would it even do anything more for performance if i didn't have the intake port matched?

 

IMO a 58 MM TB is a waste of money unless you are pushing crazy horsepower, 600 plus, or supercharged. Plus it is hell to tune the PCM on a stock motor. My "red car" motor is heavly modified engine an i feel 52 may be a little big for it. But i had the stock tb bored with new bearings and seals for the throttle shaft. Another reason i went with a bored stocker is that i could never get the Holley I had to act right.
Moral or the story if you got a big inch big HP car yeah 58 may do something for you, and you will need the intake ported to match the TB. IF you REALLY need a big TB you may consider a monoblade.

 

I have a s-trim pushing 8lbs but i have no head or cam work done. okay thanks for the advice...

 

my little 355 picked up between .1 and .15 over when I changed over from a 52 to a 58. My stock motor picked up .3 when I went from a stock TB to a 52 and a crank underdrive pulley. I have always said and still believe that its worth it.

 

having a 58 mm tb imo is worth it if you have port matched intake and good flowing heads as well.


-Daniel