hardin marine HCX slip in mufflers - expensive. Would like some real world feedback before I drop $450 on some mufflers. https://www.cpperformance.com/p-1262...-mufflers.aspx

GGB slip in mufflers would be the other option, much more reasonable. https://marineexhaust.ggb.ca

Here are the GGB inserts at work idling. They work great and pass here in Mn. My 33 (502 mpi's) and Charles Scarab 31 (500 hp's with CMI headers and the GGB inserts)

Go with the GGB's

I ran something like the hcx on a twin turbo sbc pulled them out one day it picked up 15mph it was in a 21' raysoncraft v-drive. Like to see some of these mufflers on a dyno.

Ggb....in my 598 ...5 ring made a good difference....no rpm loss.....cut one ring off so now have 4 rings

Wet exhaust or dry?

Wow, 15 mph has to be about 150hp

I wonder how big of a difference is between the “sport” and “competition”GGBs.