I've heard so many different opinions about getting a bigger throttle body, what the final ruling on such? Right now I have a CC306 with stage II heads, I have hooker LT's, Borla exhaust, and the usual bolt ons with computer reprogramming....Moser rearends with 4.10's on the way.....would I see any benefit in going to a 52mm or even a 58mm TB??

 

My opinion: With your mods, I would go with the 58mm.

Greg

 

You dont really need the 58 but I would go with the 52mm. I got a 383 with a lot of mods that I'm building and every mechanic and machine shop told me the 52 will be good. Plus you dont have to port the plenum for the 52. The plenum will take a 52 but the 58 will need some work.

 

so based on your opinions regardless of which I definitely need to get a bigger TB....okay so should I get another computer reprogram if I go with a 52MM or 58MM? Also, like carburators, can a TB be TOO big? Like if I went with the 58mm would it be too much for my mods or would the computer regulate it correctly? I assume porting the plenum would consist of take a dremel and widening the openings??

 

Thats basically what I was told. If you go with a 58mm TB the computer would only recalculate the air fuel mixture. And YES you would have to dremal the intake holes in the plenum. Well technically you dont but it would just defeat the purpose if you didn't. I was looking into it for my 383 and had asked a whole bunch of engine builders and they basically said, unless you have some huge A** HP and Heads to flow it you would be just wasting time and cash with the 58.

 

the 48 will probably be fine enough, but if you do for some reason want to get another one, dont go anybigger than 52, not worth the extra money or hassle of porting your IM

 

I would upgrade to a 52mm if you have the money laying around, otherwise the 48mm is ok. The 48mm COULD be limiting your rngine a little with those kinds of mods.

 

u should be good w/ a 52 mm

 

then 52mm it shall be....is the Holley brand good enough or is there others even better?

 

I bought a 52mm Holley for my 383 but havent put it on yet. lol motor aint done. I'd like to know the same though.

 

Have Jordan port your intake manifold. You will gain more.

ps-
why 52mm over 58?

 

I remember a while back Fred (Injuneer) mentioned that with his 58mm open 77%, it was supplying all the air the engine - a 381 ci, ported Canfield? heads, & cam LT1 - wanted (~500hp). That's about what the 52mm is wide open. This is what swung me over to a ported 52mm stocker instead of dropping the $$ on an aftermarket 58. Of course, a 58mm probably wouldn't hurt anything, it's up to you.

 

With my mods the stock 48mm TB is doing fine. I think you'll be good to go with a 52.

John

 

its like $50 more for a 58mm.. might as well go for it if you intake is ported.

 

ive heard some people complaining about those holley tbs on here so you might wanna start looking at a BBK or AS&M. i also agree if you are dead set on getting a larger tb then you may as well get the 58mm b/c they arent that much more expensive.