I noticed after my rebuld, my car got really hot in stop n go traffic when temps are above 80deg. outside. I get a tinny smell every now and then? can't figure it out??? new cats, everything works great?

 

maybe your losing coolant and burning it off the headers or manifolds...

 

You need to be sure the inlet manifold gaskets are correct, because they need to blank off the coolant flow from the front of the heads on some models. If you don't do that the coolant bypasses the heads and doesn't cool properly.

The other big cause is the radiator cap which has two valve built in and they can stick. When that happens you don't get the coolant system primed properly and again more problems with over heating.

Then also check for anything touching the exhaust system.