update: So the lower intake manifold I ordered from A1 auto is a Dorman and made in china. Its junk, it wasn't machined right and the bolt holes did not line up. I test fitted it multiple times with and without the gaskets just to see how the holes line up and they do not. So... WARNING: if anyone needs a new lower intake manifold for a 3800 engine....DONT BUY A DORMAN. A1 auto does not say who the manufacturer is on their website, I didn't know until it arrived at my doorstep. I will be sending it back. Also, One of my injectors broke, just the sleeve part where the oring goes. Can I just buy a new sleeve instead of buying a new injector? please let me know if and where I can get one at? see pic of injector below.
In the meantime, I cleaned and used a JB high temp epoxy on the pitted areas of my manifold. Im letting it cure for 24 hours before I file/sand it smooth. Im also going to junkyard tomorrow to try to find a more decent one. You can see in the picture where I applied it and how my manifold used to look. Im still not sure if its a good idea to use it with the epoxy like that, Im afraid it might break off and get into the cooling system. A new intake is $450+.
Dorman junk:
broken injector sleeve