Circulating exhaust gas through aluminum isn't going to be a good idea. if it's possible to run a steel tube the full length of the manifold and connect that tube to both headers, it might be a better procedure, just using the aluminum tube as a carrier for the steel. The firing order impulses will move a little gas from one header to the other. Since I've never had any hands-on experience with that manifold, I might be all wet!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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