I've been doing a lot of digging and see the same recommendations of exhaust length for the KE Thunder N Lightnings. But I haven't seen any recommendations for a CMI E top exhaust.

Just for the Hell of it, I measured mine on my boat since I had to have custom tail pipes made. If the preferred length of 19.4" from collector is still correct and worst length is 29.1", I'm screwed.

As of right now, I have about 29.8" of pipe from collector to exit.

Anyone got any info for preferred length on E tops with a 502 cu in? Thanks

I am in The same situation, i also need custom tails For My cmi long tube headers, 31"AVG primary lenght. All The cmi/stelling tails and collectors has huge id, 3.75"-4" Even with dry tails, why? Usually The recomended collector id For 600-700hp Car engine IS 3.5". Must Be because The marine exhaust runs cooler.