Need opinions: To EGR or not to EGR

[rpcraft]

Unless your local smog/inspection requires it I say ditch it and live life unencumbered.

 

[Daveo91Burb]

I'm not sure about your Suburban, but on my 82 C10 there was approx 1/2" to 3/4" clearance on the drivers side, and 1" or more on the pass side. I'd give you the exact numbers, but my truck now has headers.

I also took a die grinder to the ID of the manifold outlets, because they necked down to LESS than 1-5/8". According the to Walker Exhaust site, 1996-2000 C1500 5.7 liter headpipes were 2" from manifolds to dual catalysts. So, not exactly high performance stuff here, but along with the short duration camshaft, tuned for max torque at very low to mid RPMs. Enough torque down low to do burnouts by simply stomping on the gas!

On another note, make sure the exhaust manifold port openings are tall enough to not obstruct the top of the head ports. On later model 062 Vortec heads sold by GM Performance parts the exhaust ports are raised around .120", which apparently wasn't the case with the L31 906 and 062 production heads. I had to "raise" my manifold ports using a die grinder. Also, carefully select a gasket that doesn't cover up the very top of the exhaust ports.

I removed the heat shield, but I don't remember it hitting the frame. The two bosses are higher above the frame than they appear in the picture.

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Thanks for the info and tips, Mike. Helpful and I'll definitely check for matching ports between heads and manifolds/gaskets and grind as necessary. Still not sure which manifolds I'll use. I can use the TBI manifolds and not have to change the Y-pipe, or I can use vortecs or ramshorns and get a custom pipe made. I might get the motor in and running first with TBI manifolds and then later change to one of the other two options. I really want to eventually replace the y-pipe with either a custom made one or a Walker - if there are any that would work. I think factory pipe is pretty restrictive. Also may go with duals - so many options!

 

[Derick C.]

I think the factory Y-pipe is only 2 1/4 dia. I built my own several years ago in my 92 with 2 1/2 into a single 3" where the y pipe comes together

 

[Daveo91Burb]

I think the factory Y-pipe is only 2 1/4 dia. I built my own several years ago in my 92 with 2 1/2 into a single 3" where the y pipe comes together

Yeah, they're known to be pretty restrictive. I'd love to be able to make my own, might be a little outside of my skillset tho. Do you start with pre-bent sections?

 

[Derick C.]

Yeah, they're known to be pretty restrictive. I'd love to be able to make my own, might be a little outside of my skillset tho. Do you start with pre-bent sections?

yea I ordered some pre bent 90's and 45's

 

[Daveo91Burb]

yea I ordered some pre bent 90's and 45's

Are you able to post a pic or two of the homemade y-pipe? I'm thinking of trying to do this.

I've decided I'm going with the OEM vortec manifolds. I have a good set of original GM ones now (picked up the DS one at pick-n-pull yesterday for $35) AFAIK all the vortec trucks had the single exhaust on the PS, so there's no possible way of buying a pre-fabbed y-pipe. And the DS vortec manifold exits out the back at an angle instead of almost in the middle straight down like the original TBI manifold. It's possible I could buy a Walker 40317 and modify the DS inlet to fit the vortec outlet but maybe it would just be better to either fab my own or have one made at an exhaust shop.

 

[Derick C.]

Ill take pics next time I put the truck on the lift.