Yes, dont believe that 150k/5 year shit GM puts on it. We've had to do so many intakes on 3.1/3.4 and 3.8s with cars that had dex cool. 1 car the dex cool had etched into the heads a little, and seen another car where the overflow was filled with sludge. And all of the 3.8s we've done, the egr tube gets eaten thru and the intake fills up with coolant.

Though does coolant flow thru the upper part of an LS1 intake, or just the lower?