you dont need to ship the bottom end for a 4 mill unless your worried about putting back together. (its really easy with a clymers and bigred350x's walk threw) i would say the 115 rod case ya ever wanna do a cub or serval. shipping cyls is easy fit in a medium flat rate. and youll need a cool head and some cut domes for a 4 mill.. and yes if ya go with a 115 youll need 795 pistons but whats the big deal if your dumping all this money into a new motor why not get new pistons?