Novarossi's were my first engines, I went with a r2r 21-4 from Monty, it came, I clutched it and went racing....totally painless engine, a complete breeze to tune(Odonnell 97T plug is what I prefer and have had great luck with) I have never had one bad day at the track due to engine probs, however I was lean bogging a tad on my last race due to the fact the mill was at 6 gall. and had a leaky front bearing......I got 6 gall. and only needed to replace a rod and went ahead and had Monty do cermaics f/r as well, rest of engine was perfect, the pinch is right where it should be, I wasnt afraid to let it see 260 and thats normally where it was at.....I ran a Ofna 053 pipe with the stock ] header and Byrons Gen2 fuel.........be anal about filter maintenance and these engines will give you countless days of great consistency and good results, if not it may not last a day, filter maintenance is a MUST........Im racing my 1/10 electric cars now as its winter here, but im ready for spring and some nitro.......Novarossi USA baby