I'm going to take a different direction here, although there have been some valid points made. Why don't you want to build a 351 Cleveland? Ford didn't stop selling them in the USA because they weren't any good. They made them in Australia for decades! All the previous arguments aside, a 302 block(except Boss 302s and Ford Racing blocks) will not take the punishment a Cleveland will. That's why there are main stud girdles for 302s available in the aftermarket. Cleveland heads flow so much, that some builders install restrictors in the ports. Smog regulations, high insurance rates, and Ford dropping their race program killed the Cleveland in the USA. But when Bill Elliott started dominating NASCAR in '83, a lot of people started shopping for Cleveland parts in Australia. Jack Roush used Clevelands in Pro Stock.
I'm not aware of any successful use of Windsor-based engines in NASCAR. But I never imagined Mustangs having their own drag racing classes, either. I'm guessing there's a lot of hacking going on in those areas to stay competitive, as it was for the buick Grand Nationals in the '80s. If you've got a 351 crank, and a friend that knows what he's doing grinding cranks, go for it! Get an engine bearing catalog for research, it'll save you some time. As they say, 'speed costs money, how fast can you afford to go?'. Learning can be costly too, if you go over budget.Good luck. JD