new intake now overheating??

Maybe one of the coolant ports got blocked, or the tstat could be in backwards. Also, if you didnt "burp" the system, air could have been trapped, thus killing your cooling abilities. I dont know of anything to do except take it back off and try again. But hopefully someone will chime in and give you some more ideas to save you some work. Hope you get it figured out!

Add some more details about how it overheated, as we can give you some better ideas.

It's an air pocket. No big deal. Here's what I do when adding coolant after a mod - once the radiator is filled, I unscrew the ECT sensor - the highest point of coolant on the motor, then use a funnel to add coolant, slowly right though the ECT opening. When it's full, it'll seep out. Then put the ECT back in, Fill the radiator about 80%, start the car with the radiator cap off and the heater on high. Wait about 4-5 minutes until the thermosta opens - the coolnat will suddenly drop - and then top off the radiator and put the cap on. Be sure the overflow has plenty of coolant in it. Then stop the engine. Let it cool, and pop the radiator cap and topp it off again. Should be good to go - you may have to drive it and do a couple of hard stops or quick right/left turns to work all the air out. But if you filled the overflow enough, the air'll be burped out and the coolant will be sucked back in when it cools.

Don

It might be that one of the gaskets (intake to head) is on wrong and blocking a coolant passage. I don't know how to tell with the engine assembled. Did you check the t-stat before installing it. I have seen several brand new ones that would not open (or only open a little) when installed. As a matter of fact I check every new one that I buy to be sure it will open because of having one new one installed (a great pain in the McDonalds parking lot!!) and the Jeep still overheating and thinking that the overheating problem was something besides the thermostat.
If the burping thing doesn't help, pull out the t-stat and boil it in water on the stove. You should see it open before the water boils, or it might be bad if it doesn't. Hope this helps some!!

Phil