I aquired one of these recently.  A beautiful piece but on the test stand it came at me like a hungry gator.  I had Jim  Lee make a new much smaller Venturi and relocated the spray bar.  I'm going to try to tame it for my Supermaster without a pipe but I'd say it's a great candidate for a pipe.  I sense this has .60 power but needs a leash.

Dave

I don't know which I have but here it is with Jim Lee Venturi now at about .156 and new spinner adapter.  Haven't tried it yet with this set up.

It's 11.8 oz. as shown.

Thanks got your pix Michael.  That's not the Venturi that was in mine.  It was quite long and the spray bar through the center further up.  It was new but I think it might have been an R/C version conversion attempt. 

Dave

There definitely is a way to stop that engine from running away - but you are not going to like it.

Whack a diesel head on it, these engine are built like brick outhouses and take to the conversion well.

That would have been an option. But the drug addicts have made it so hard to get the fuel here.

I am surprised that you are even talking to me after the diesel suggestion, but I too have an older Modela MVVS 40 with an AJC diesel head on it!

That said I have always wondered how the standard tuned muffler would work with something like a double length header pipe at lower rpm. The standard pipe cuts in at 13000 rpm and suits the 40,45 and 49 range so I am guessing the smallest engine with the biggest resonator just may work at a longer length.

I have heard of the reverse being true, a smaller resonator upped the pipes start point to a higher rpm, the real problem here is that MVVS resonators have about a 3000 rpm operating band and produce broad power.
So you will have to find if there is any limit point definite enough and low enough to be of any use to you.

Power boat guys reckon on a double length header as a good place to start experimenting with.

Good luck.

I had the R/C version. Served me well in Q-500 racing. Hot motor

I have this old MVVS 6.5cc (40) that i bought a long time ago. I have never got it to run well. Always runaways, what ever i did. I have the 8 cc (49) Acrobat that runs lovely with or without pipe. I have compared the porting (just visualy) between the  6.5 and the 8.  The transfers are much lower compared to exhaust on the 6.5. So my question is: Can i get a good run with a pipe on the 6.5.
 
Michael

I sold  quite a few of the  40s that have low time, they  work  OK  for  piped  stunt,  the high times versions  do not, and  A   PA 40  ,
OPS, or  OS  VF   are  better  engines  for  F2B

regards

Randy