Just to be able to hit the track change valve springs,49 jet, while carb is off make sure butterfly in bore of carb is opening all the way up normally purple plates aren't this is to just get you on the track.it needs a cam change, timing checked, spring presser set carb flowed to be top notch hope this helps
There is a huge difference between a small plate (purple or blue) flathead and an unrestricted. Can it be done? Sure. Will it run like the engines built specifically for the class? Probably not. Our purple plate carbs are considerably different by design than our unrestricted carbs. Likewise, the valve timing, valve springs, ignition timing, portwork, exhaust and a whole lot more vary greatly. Actually, we have successfully used the same cams in both small plate and unrestricted engines (certainly for momentum oval tracks.) Cams like the old 95-3 and 96-3 work very well in both applications (small plate and unrestricted,) but the set-up of these cams through open and close, overlap, etc is much different.
If you've got specific questions, or are needing a hand at this work, give us a call - we'd be glad to help you all we can.