Start early, it will probably take most of the day, it took me longer because I port matched my LIM runners, I wanted them 1.9x0.9 like they all should have been, but were not due to poor casting, I also knocked a lot of the rough down inside the runners, not necessary, but I wanted to get some use out of my dremel..
Do you gave any JB Weld on hand in case you find any small pitting on the LIM?
I had a few small pits, to be safe I filled them.

Thx William..Ya I have some Jb weld - hope I dont need it !

We just had a 45 minute power outage..
Glad power is back so quick. Home A/C is getting a work out again..90F in Sun today !!

Power going out when it is hot sucks, last summer we had a bad wind storm and trees knocked out the power, it got up to 99F, and we were without power for a week.

Hopefully you won't need the JB Weld, I could have done without using it, my pits were really tiny, but I filled them, and used a razor blade to carefully scrape away the excess, it turned out ok..

I personally won't use dorman upper intakes again. A few year ago I installed one on my coworkers Grand Prix. Three months later he said it was ideling rough and making a whistling noise. I found the EGR stove pipe had actually burnt a hole in the top of the manifold where it comes out of the LIM. He was able to get his money back from the part store he bought it from and bought a GM intake and hasn't had a problem since.

did you change it with the one that comes in the kit?

The kit comes with a reduced diameter stovepipe, as Justin said, did you replace that old EGR Stovepipe with the one included?
From what I have heard the EGR issue has been an issue some have no matter what brand of upper intake they have, I replaced my EGR Stovepipe and have not had any issues so far.
If I were not going to use the Dorman upper intake manifold I'd go with the one sold via Ineedparts, it has a steel bushing in it to help assist the reduced diameter EGR Stovepipe in keeping that port from getting warped from heat.

GM Intake Manifold Kit

Yes I did install the new stove pipe that came with the doorman kit as per the included instructions. It just melted for some reason.

Yes I did install the new stove pipe that came with the doorman kit as per the included instructions. It just melted for some reason.

That is hard to understand.....that stove pipe is smaller than the opening in the upper plenum, and should not have made contact with the plenum, to melt it....

Sure you didn't have an EGR or cat problem? That would have increased the flow of hot gases going into the plenum and raised the temp of that pipe....

It did not make contact, it melted on the top of the plenum above the stove pipe. I wish now that I took some pictures.

As Gus said there may have been some issue causing the EGR gasses to increase in temperature.
I am pretty sure the upper intakes are made of basic Nylon 66 material, and its normal operation range is -40F to 185F, its melting point is 480F to 500F.
It can handle up to around 66 psi at 430F before it starts to deform from heat while under pressure, the higher the pressure the lower the temps required to allow it to deform.
Moisture can cause it to platicize though..

https://www.calcentron.com/PDF_Docum.../materials.pdf