high mileage reliability?

this really isnt a civic question but i found an integra gs-r for a good price. the motor has 307000 miles on it though. if i rebuild the valve train with all jun products and then replace all the pistons, rings, connecting rods, and sleeve it, will it be a reliable racing engine. i have quite a bit of experience but not with a motor that high mileage. i think it would be fine with all new products but what do you guys think????