Hey guys sorry for not replying im out east on a course.
The 2.7 Throtle body is bigger and less restrictive. I think i measured at 2-3mm bigger. Also does not have the mas air sensor in the throat. The 2.7 also has bigger injectors.
You want a good setup.
2.7 motor with a bored out TB and a 3" intake with the mass air plumbed to a air box other then stock. A 2.5" DP and a full manderal 2.5" exhaust with a resonator and a flow master muffler.
As i stated last year i will be building a turbo kit and a procharger sc kit for the gv when i get my house this summer.
I have long tube headers on my gv with alot of other mods but my biggest prob is not being able to do any timing adjustments and fuel.
Here is a quick vid of last summer. truck need a alignment and was leaning out up top.