Good thing we don't charge by the question!!

If you're just going for a putter with a little more beans a 650 is plenty, though you might consider an Edelbrock or Street Demon carb as well. They're just a little "friendlier" than a Holley. For an intake the Edelbrock Performer (not Performer RPM, there is a difference) is the old standby. It's great for most "in town" driving. The RPM is for higher rpm power curve.

The question comes to mind; why does it need head gaskets? Your answer might mean you have other issues to deal with.

On the chrome dress up kit, avoid the low priced ones the "include everything for $19.95 (or whatever low ball price) they're JUNK!! Even if you're carefull about not over tightening the VC bolts (which you should be), and have the good neoprene VC gaskets, they'll still leak. You want ones that have good rigidity, and are straight, along the mounting surface. The tube you're calling a breather is mainly a chimney to bring manifold heat to the intake air for faster warm up and sooner choke opening (one of the emmissions things they did in the '70's). Chuck it unless you have inspections that require it. Then you just need to reinstall at inspection time.

Where you buy the stuff is your call, but having the option to deal with a local supplier sometimes pays benefits later if you need to exchange something, or get other stuff. Usually they tend to be more helpfull to repeat customers.

As for replacing the other stuff, that's a function of what needs it. The thermostat is inexpensive, and while you've got it apart, what the heck. The distributor is another matter. Only replace if it's worn, or defective in some other manner. Replacing the cap, rotor, and wires is also a matter of condition. If it's HEI and you want good parts you're looking at $80-100.

Torque specs you can find in a Motors manual, or even online with a simple Google search.