Must have been from when he was still experimenting.   

Good call, Larry - the slots are actually .018.

The muffler was packaged wrong from Fox. I flipped the baffles over and you can see that they are indeed countersunk.

No, I'm not making it up!! Check out the photo of another one, never opened.

Bob Z.

Good Price !!

    Just looking at it, it appears you get what you pay for!

    Brett

    Just looking at it, it appears you get what you pay for!

    Brett

Ya mean that maybe all its worth?

Ya mean that maybe all its worth?

   I don't know for sure. What's the scrap value of aluminum theses days? Figure the screws cost about about 1/2 a cent a piece, probably about the same aluminum it would take to make 20 pop cans.

   On the other hand, after the engines seizes from overheating, it *will* indeed be much quieter!

   Brett

I have had one of those go through my hands.  It is designed to fit a particular one of the older model Fox 35's which had flats on either side of the rear of the exhaust stack.  The horseshoe seats against those flats and puts no distorting forces on the crankcase.  The usual strap on muffler can distort the crankcase and cause binding.  It is actually a pretty thoughtfully designed item.

Hi, Larry - actually, the slot length is only .95, bringing the area down to .051 in².

But, like all discussions, we can speculate all we want but the true resuults can only be determined by test.

So, I will perform one on a stock Fox 35 and see what happens. The usual - before and after, monitoring speed with a tach, head temperature with a thermocouple and run time with a stopwatch.

I do have some concern about temperature. A few years back, I tried one of those tongue mufflers with the removeable sheet metal baffles on a Fox 29. While the engine was not damaged, it ran noticeably hotter and the power was down.

Bob Z.