Alright I tried searching here and through SilveradoSS.com and couldn't find a simple answer.

Does anyone know the size of a factory 6.0 throttle body?

 

I believe its 78mm.

 

So far, that is what I've heard too but no offical confirmation yet.

What is the 4.8 & 5.3, 70mm or 75mm?

 

Im interested too. The stock one on 4.8 and 5.3 is 75mm. I would love to get confirmation if the 6.0 TB is 75mm, 78mm, or 80mm as Ive heard that all were correct.

 

I can't say for sure about all years/combos, but my 2001 6 liter and 2002 5.3 were the same size as my buddies 1999 5.3. He came to me after having read where the 6 liter was supposed to be bigger. We measured them with a caliper and they were the same (I can't remember but I want to say it worked out to around 75mm) Even after standing there and observing the measurements he still insisted that the 6 liter TB was supposed to be better so I offered to trade with him for $25. His inferior '99 5.3 TB is now on my 700hp motor lol.

 

I wonder if the 3/4 ton LQ4 6.0 is the same size but the one's in the LQ9 SS's and Escalades 6.0 are larger?

 

I had read in Handzell's book that the 6.0's were a smidge bigger than the 4.8-5.3's, but I don't believe that to be true. I did find out that the earlier 4.8-5.3 tb's have a different part number than the 6.0's, but that could be for a number of reasons. I recently bought an 02 6.0 throttle body from ranwalk because I want to try some home porting and polishing, and I figured I'd measure my 99 5.3 tb and compare when I do so. Unfortunately it's gonna be a while before I can get to it because I just had surgery on my right shoulder and elbow about 3 weeks ago, and can barely lift my arm let alone turn a wrench

 

I also thought the 6.0L TB was 78mm. Maybe Richard/BigTex will chime in....

 

Hey, I've got a never used 6.0l fly-by-wire in my garage. I can go measure it, if needs be. Anyone have any use for it?

Will

 

Possibly, depending on price of course.