There should not be a big difference, but I have not yet tested it.

Here is the situation.

I tested the MVVS/Evo 58 first with a Slimline muffler modified from one for a DA50. That one did 6800 rpm with a 24-10 Mezjlik prop. This muffler has 7/8" OD outlet pipes.

I then retested it with a header/canister setup. I expected great things, but was disappointed to see that it was exactly the same 6800 rpm.

I have run the same engine on our newest Bisson quiet muffler with 5/8" outlets but have not measured it with a tach. IT seems to be down on power from the canister/slimline which is expected by my observation, I'd guess it's in the 6300-6400 RPM range now.

I also now have a Bisson muffler with 7/8" outlets but have not tested it yet. I am expoecting it to be similar to the slimline/canister setups.

Remember that with the Bissons they crimp the tips of the outlet pipes down to a very small hole for noise reduction. You can always cut off the tips to decrease backpressure which in most cases will increase power.

TF