The new ones have a different carb. When I was in St Louis this year it was 105 degree's with very high humidity (its very humid locally as well) I only tweaked my high end needle 2 times all weekend and after my mains ( I bumped a couple of times) it came off at 225 with a new exergen temp gun and it was very fast. Their are now several guys running these engines in my area now and everyone is performing very well. Seriously give them a try they are the unknown line of good performing engines and they last as long as any other italian motor.