Just got a Slimline sport scale muffler and I need to put a pressure fitting on it. just wondering if anybody could lend some advice on the best place to tap it in to get the correct back pressure for the tank. Thanks


Engine is a O.S. .46 FX ( in case it matters)

On a pitts style muffler I try to put the pressure tap centered between the exhaust pipes so the exhaust pressure going to the tap is balanced. This, however, is not always possible (or practical ). Locate the tap so you not only have access to it, but so the tubing will be routed so it is not resting against the muffler, motor mount or engine (heat and vibration will wear through it ).

Another possibility you may want to consider is to put the pressure tap in the center of the backplate of the engine instead. If you decide to go this route, I suggest cleaning the backplate well, installing the pressure tap and JB Weld it to the OUTSIDE of the backplate. When the JB Weld is cured, grind the pressure tap so it is flush with the inside of the backplate to insure the crank will not hit it.

Tap the fattest part of the muffler. It doesn't matter where on that part, as long as it's somewhere on that fat part. (red area)

Thanks for the info,

Minnflyer, Where do you get all those awesome pics?

Minnflyer is a paintshop master as well as my hero

Personally I would try to get it directly across from the header as I would assume the pressure would hit there first, but chances are anywhere in the red section would eventually get the same pressure it's not that important. Perhaps underneath where you can almost hide the exhaust line (if you can get away with that...)