Does anyone know the mm size of a average ported ls1 throttle body. I would like to know the before and after diff.

 

I was wondering the same thing, I would guess it would only be a difference of a mm or two.

 

Probably, but what mm size is the stock one. I'm sure the polishing helps the most.

 

stock is 78mm

 

Stock - 72.5mm
Ported - 75.5mm

 

So is stock 72.5 or 78mm?

 

A stock throttle body is listed as a 75mm throttle body. The lip in front of the blade (which you remove while porting) only makes it around a 72.5mm throttle body. Make sense?

 

Thanks. Good to know info.

 

Yes, the blade and the housing around the blade is 75mm but the lip in front of the blade is what your taking out(among other things) which makes the TB a true 75mm.

 

are you still messing with any of these anymore? if so pm me...

 

Thanks for the tip, Bo.

I did mine last week, but was afraid to work on the lip. I must have misunderstood the other posts I'd read...I thought the lip needed to stay (at least some of it) or it would be the end of the world. I guess they just meant that you don't want to get into the opening and make it bigger than the blade.

Is that correct, then, that you get the lip but don't go bigger than the blade?

I feel like such a newb...

 

the early truck t-body are 78 mm good for an extra set of ponies ,but the car's t-body are 75mm

 

Does anyboby know is there a place you can trade your TB in for one that is already been ported?

 

yes thats what i want to know any one

 

I havent seen a 78mm TB on the trucks, doesnt mean that they do not exist- Ive swapped blades in and out of em with the vette and fbody ones because of various reasons without a problem. The bleed hole on the truck TBs(70123 part # blade I believe) is however smaller than the fbodys by about .020"

 

Doing the port and polish, does it help with the performance a lot. I'm running a turbo kit so I would think it would help me a lot, or should I buy a aftermarket one.

 

what size turbo are you running? and if you have the money yea, just get a bigger TB....a ported stock tb will give you a nice upgrade for the amount of time and effort you put into it....

 

Cablebandit ran one of mine for a long time with twin turbos(incons I think). He seemed to like it pretty good and it was an older port design.