I have a set of the KE long cast aluminum headers. I am in the process of building a 555. I want to know if it will be ok to run them on an engine dyno without water running through them? My concern is that the aluminum will get too hot and possibly warp or be damaged. I know I can probably just rig something to dispose of the water but is it necessary.

Yes you need water running through them. I would think that they would melt on a dyno pull without water.

Agreed, water is mandatory.

if you run them without water,they will be scrap metal,DONT DO IT,they are a very good flowing exhaust.

What they all said.

Use dyno headers or make sure you have plenty of water flow though the KE's.

For the record, are you just running it for a #, or are you going to tune it? Mine was tuned on dyno headers, then installed the SM manifolds for two pulls.

Tune it whit the KE headers and make sure that you cool them !
Water cooled headers flow different then normal headers due to the cooler exhaust temps .

And if you want to know if the do a good job look for a pair stellings and compare them you will be very happy whit the KE !!

We had stellings on a blown 509 and swapped to KE

THANKS GUYS. Not sure if we are going to tune or just make a pull. I would assume we will be tuning, my builder said he would have the dyno all day.

Interestingly enough we planned to do a bunch of runs too, turns out the Holley was damn close right out of the box, we dropped one secondary size and that was it (could have gone two but everything I did was fairly conservative) We saw 20 something horsepower difference between the dyno headers and the SM manifolds, I'd need to look up the exact difference...

What size motor did you dyno? What holley carb did you use?