The only problem I see with you choices is the pistons. They are for a LA block which has a taller deck height. Those pistons MAY stick out of the top of the deck. Their compression height is 1.465. You may have to use a thicker head gasket to get the compression you want. ICON does make a Magnum specific piston with a 1.445 compression height.
The 745's will stick out .003" from a nominal Magnum deck. Use a Felpro 1008 at .039" thick and you'll have a nominal .036" quecn/squish gap.... will be nice. Adjust as necessary....
