Throttle body /intake manifold size

**David Ray** · 09-01-2009, 06:36 PM

If I have the LS6 intake manifold on my '01 Z28 then what size is my throttle body...80mm? I've read that the earlier LS1 intake was 75mm. Is there a significant difference and should I consider going to like a 85 or 90mm?

**Cutlass** · 09-01-2009, 06:40 PM

You have a 75mm TB. 85mm and 90mm won't fit without an adapter plate and its pointless anyways.
If anything, I'd recommend a ported and polished stock TB. You can do it yourself or have Mark Shaner do it.
http://www.s2performance.net/F-Body.html

**David Ray** · 09-01-2009, 07:00 PM

I believe (though not sure) that my TB is already ported. Compared to the pictures on the site you provided, mine looks alot like the thin-walled one on the left. It also has a small hole in the upper right portion of the body. It's filled with an orange sealant. I've wondered if it wasn't once an entry port for nitrous or it was damaged from the porting.