Originally Posted by Grinder

The 35+21 was more powerful than the first flash. The second version called the flash special was faster than the original flash .21. The flash special had a lighter piston which was already used in the 35+21. That helped it's performance, and durability.

Performance also depended on what internals novarossi decided to put inside the engines. Some were faster than others. The same engine could come with a variety of crankshaft intake window sizes. The small window did not make as much power as the large window.

The new PT, and PTS are very nice engines. They are the fastest stock novarossi engines yet. It is like the flash special with the large crank intake window. It has a very slippery coating on the piston, and nicely redone case internals under the carberator. The fit, and finish is very nice. The engine runs, and idles great. I think that piston coating helps a lot.