how much heat do you need?
I put the 6" on my 0-320 with typical crossover. I can't imagine why you'd bother with a 4", more heat is always better, right? The 6 is just adequate in my opinion. I'd recommends wrapping the pipe with some kind of heat transfer material; spring coils, stainless steel wool, etc.
call Robbins, they probably have more feedback for you.
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Perry Y.
RV-9a - SOLD!....
Lake Country, BC
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