1.whats it for? ive also heard the 4th gen has no radiator cap or over flow tank. can u just hook it up to where the over flow tank goes on the stock 3rd gen radiator, and have no overflow tank? any extra info or adive on the steam tube would be great.

2. also does the ls3 have a a coolant lines that run threw th throtle body like the tpi motor?

 

1) Vents steam from the 4 corners of the cyl heads to prevent hotspots. 4th gens have both a cap and overflow. The cap is on the rad, overflow under the battery. The steam line must be teed into the pressurized coolant system somewhere. Most common spot is to drill/tap the WP. I didnt like this so I teed it into the heater core lines. Teeing it to the overflow tank will do little more than create a bunch of bubbles and slowly empty your coolant

2) Yes, and just as easy to bypass. The steam tube actually feeds one side and the other side went to a special port on the radiator which your 3rd gen wont have

 

see post #98 in my thread for how i did it on my ls3 swap

https://www.thirdgen.org/forums/ltx-...ne-swap-2.html

 

here u go:
http://www.kurturbanperformance.com/...or-system.html

im probably goin to be using those fittings.

 

a bit overkill, but it does look purdy