somebody here help me with this if you can.i have a 91asp redhead,it is the older one i think,it has the round cylinder head,i read something once that menthioned about the markings on the box something to do with the colors?this one has a silver stamp with 91as in it,box markings say I.S.C international Indianapolis IN.address.I'm not sure if this one has the new style carburetor or not.it runs pretty good.it came with the extra head shims and i was told to put two in so i can run 10%nitro.anyone with any information or any links please post them...thanks