My 360 build.

the machine shop I use charges 180 dollars for an external balance...internal that requires Mallory metal will hit 400 dollars...

you have the cost of the Mallory metal plus the additional drilling of the crankshaft to press the Mallory metal....

just have it externally balanced....rod..crank..pistons with pins and clips.....one rod bearing...one set of piston rings...balancer...and weighted flexplate...