Will removing the webbing from the upper intake have any detrimental effects without opening the exhaust as well?

Anything to improve air flow is always a plus, intake webbing is a free mod just costs time, also for time being if you are cash strapped, remove downpipe and with judicious use of big channel locks & or vise try to make the pipe as round as you can, new pipe is best, but again any flow improvement is a plus.

Generally intake webbing is L56 "S" vin engines, I don't know of a F vin truck with webbing.

Sounds good thanks. BTW, I just removed the upper intake and I'm surprised the engine hasn't had an asthma attach!!!! If I'm careful can I clean out the lower intake (as much as I can get to) without removing it?

I just did the very same mod 2 weeks ago and it did wonders!! Make sure you make the upper as clean as humanly possible. I used Red can CRC Brake cleaner to get all the goop out and then used alcohol to clean it all out when I was done modding.

To clean the lower part of the intake, you will want to use lots of rags to get the goop out and then I wiped down with a rag soaked in isopropyl to get out all I could.

Don't forget that doggone EGR donut gasket that is in the middle EGR pipe or you might be opening things up again. The part number is DELCO Part # 219167 or GM Part # 10191428

I took some pics of my downpipe and it was attrocious. I got a *huge* pair of pliers and tried to round things out since it was so badly pinched. I will post pics on imagestation tonight as I am away from the machine I dumped them from the camera to.

Good luck!!

Suck & scrape is method I used, use your shop vac (use the house vac and you are on you own with the wife :eek: ) to remove the junk as you break it free, the stuff is soft & digestible by the engine/turbo big chunks make it harder, messy as heck does not like to wash out. dont forget to replace donut gasket between upper & lower intake (see pic on my site below)

TD, I sent you a PM.....

The upper intake mod is great, and the price can't be beat. I used my drill press to drill several holes first, then I just connected the dots with my jig saw.

You got Mail :D TD, I sent you a PM.....

What are the pros and cons of blocking the EGR?

Performance no down side, Smog cops is a whole nuther story you are on your own should you decide to do this "off road use only" is only legal way to run this configuration.

Do yourself a favor, and pull the lower intake. Then after cleaning, use intake gaskets for a 6.2 J engine or better yet, see if you can counterbore the intake and install a frost plug at each EGR port...