Thanks Don and good to see you out in the forum!

Not very much room for a large resonator although this model is running a form of tuned pipe just before the exhaust stacks. On my website
you'll find a page where I did explore some exhaust designs because I do like to attenuate the sound, I can't abide the shrill high end
of a lean 2 cycle myself these days. Believe me this engine is moderate by comparison. I don't know if I'll take the time on this one to take it apart and replace the first stage of the exhaust system but I have a modified form of it using bronze wool packing that is somewhat effective.
That in tandem with the second stage of this one may attenuate the sound even better and still give decent performance.

Love to, and I do actually on two of my other models. Problem is backfires if not set up just right. On just about any other type of model
a backfire is just an inconvenience but when you've got drive line and starter components attached to it backfires are way more than just annoying. Look at my first thread I referenced above for the account of running an OS 48 using CD ignition and gasoline. Backfires where a real problem until
I implemented TCSA. Then what killed it on gas is I could not keep it cool. Now water cooling would likely fix that but not many current production 4 cycle engines that will fit in a 1/10 scale model will lend themselves to a good
water cooled configuration. The radiator, fan and water pump are not the issue it's the shape of the cylinder; water cooling just the head isn't
nearly enough for safely. At one and the same time not wanting to either do major surgery to a $100 cylinder without a real plan or wanting to machine my own heads and cylinders I stick with the proven formula of what you see in the latest Panther video. I'll probably use 4 cycles in some models
but if they have the transmission /starter/ engine configuration as this one it will likely be powered by a Webra.

You have to remember I don't just have one of these gas powered tanks, I have 'a number' and I wanted a reproducible and consistent
engine package that I could rely on. The old Webra 6,5 ( 40 ) blackhead is it. Tough, powerful and durable. This engine is 31 years old.
I originally sold this model new when I had my business and was able to buy it back little used 5 years later and completely took it to pieces before rebuilding and repainting it. This one IS due for some serious detail upgrades but I'll defer it to when all my other projects are further along. I still have my original I bought in 1976-77 and it also runs well but the engine could use a new ring; it saw a LOT of running over the first 6 years I had it.

If you look over my website you'll see the other tank of mine with a 4 cycle, an OS .20 4 cycle - my little Hetzer. It runs well but isn't so quiet either.

There are some other modelers out there in the gas tank arena and some are running 4 cycles. They do sound a little different but hey they are
never going to sound like a Maybach. These are small engines producing their power at speeds many times that of a full size tank engine; it will
never happen. I now warn visitors to my website's video page that my models aren't going to sound like full size. To most they're going to sound
obnoxious but I don't pretend that they're anything but what they are. I don't want to offend people with the sound; I know there are those out there who
revel in being obnoxious, I'm not one of them. I like to attenuate the sound as I say but there's just limits to what you can do
and to a degree I've grown to appreciate the sound of one of my healthy engines running well. Rather like a proud dad watching junior ride
his bicycle..with playing cards clipped to the forks.

These things aren't always easy to set up taking patience ( I've cursed plenty ) and maintenance.

When I run out of patience I turn to my Tamiyas and others...

Jerry