What's on your "to do" list for this winter on your race car?

Not a race car per say, 73 Duster, but changing out my MP 380 hp crate motor for a 505hp/517 tq motor built by shelton racing engines in Georgia, 904 trans built to handle 600 hp with trans brake, 3k stall, new tti headers and new gear vendors ( of course a GV showed up on Marketplace for 1k less after the new one showed up)
Deciding on upgrading the 28 spline Ford 9in to 35 spline. Not doing the work myself as I'm just an average dude