360 magnum to 408

I had an offer of 325 for an MP stroker crank new, and had some one else mention a set of KB pistons that would do the job which were under 300 and if i use the stock rods with arp bolts with machining and balancing around 600, rings, gaskets, bearings would bring it to about 1700 which is right around the price of a kit only. Also after much thought on this if the pistons would hang .120 out the hole with stock pistons then the crank is not really a full 4 inch stroke so part of the stroke is in the 1/8 inch raise in compression height so.. the crank is actually a 3 7/8 inch piece. Im not really suprised that you cant just buy the crank only and install it with out the "matching" pistons. If anyone knows of a crank that will just bolt in without having to buy pistons I'm all ears.