Vortec EGR System?

**pmkls1** · 05-30-2013

Well Mark, I may be a little late chiming in here, but I just happen to be resealing the intake on my grandfather-in-law's '99 suburban. I snapped some pics of the bare intake to illustrate what I believe may possibly be the issue. The particular truck that I'm working on is a 1999 Chevy C2500 Suburban with an L31 5.7 (obviously) and a 4L80E. Mechanically, the '96-'02 L30 and L31 intakes are essentially identical AFAIK. Anyway, I've got a couple things to do and then I'll upload my pics to the computer and post them with a few notes showing the passages and such.

**Hog** · 05-30-2013

There are some small EVAP differnces between the 96-97 and 98+ intakes, but the 305 and 350 intakes are NOT differnt.

peace
Hog

**pmkls1** · 05-31-2013

Alright, the first pic is of an assembled manifold with a few things pointed out for anyone not familiar with the layout.

**pmkls1** · 05-31-2013

The next pic is of a bare intake in the same orientation.

**pmkls1** · 05-31-2013

Sorry for having to post one pic per post, but I'm having problems with posting. This next pic is a close-up with the EGR passages pointed out.

**pmkls1** · 05-31-2013

This next pic illustrates the difference in distance that the EGR gasses have to travel to reach the runners. The bank 1 ports in the pic are for cylinders 1 & 3 and the bank 2 ports are for cylinders 2 & 4.