NAH, it's not worth rebuilding---I'll give you $100 for it just to get it out of your way-----! Just kidding-these are very desireable engines. One was even used in an Indy car in the fifties--many, many of them were used in the sprint cars of the 50's and 60's. Check out Hot Rod magazines on Ebay for a cover photo of one modified to the max. with a Wayne head.--I think it's Dec. 1954 issue.
As AFU said, check ALL the local parts stores/machine shops for parts prices before going to the catalog suppliers--they're usually much higher.