Might contact V8 Speed. They have molded hoses and maybe know the part numbers they used.
I usually take a welding rod or metal coat hanger and cut and bend it to fit. Then take the two pieces to the local auto parts store and look through their inventory for a hose that matches the bends.
I think the LT4 and LT5 both have the same Corvette water pump so the hoses Mark Stielow used on his LT5 Camaro should work or be close since he had a C&R radiator. They are readily available. You can look at his build and do a visual check.