At any other track in the country they do not get a break. You want to run open, you run open rules. You can choose any motor you want in the open, but the weight is same no matter what motor you choose.
At the Got Milk race. which was a little bull ring a 250F made the feature of 14 out of over 40 opens.... However at Millbridge they might be able to keep up with the slower 500/450s they will not come close to what our track record is in an open. 250 two stroke might be a different story. There is a guy going to run one next week at Millbridge so we will find out.
They do pretty well on 1/8 mile and shorter tracks keeping up. There are some heavy hitting 450's that are able to run the big tracks and keep up with the really good 500's. You will have a couple of really good 250's that are within a few 1/10's of a 500 and the good driver can make a couple of those up. So I guess I am saying you can be competitive with a few of the opens, but the better open drivers will be a few 1/10's faster. Run within your budget and try to build up. Starting in a 250 will not hurt anything. If you can learn to keep up in a 250, once you can afford a 500 or 450, you might start winning some races! Best of luck to you.
A 250 2 stroke can do double duty in my Unlimited All-Star flat kart too, so I'll probably go that route. I was going to say I wouldn't run a 250f, but I'll be showing up with a YZ125, so I guess I can't really say anything.