Assuming the crank and rods are stout enough, Wiseco can make you some custom pistons for around $600. Then, you can take your cam to a grinder like Comp, have them weld up the lobes, and regrind it. Making an intake for an inline engine isn't too difficult. So, I don't see why it would be impossible. If the rods are weak, you might want to look around for similar sized rods in other engines and get the crank/rods machined to fit.