It's been cold here in Florida. Got below freezing for a few nights.  My Tbird was in my garage.  For some strange reason, the passenger side exhaust manifold has begun to burn off white smoke vapor when I first start it.  It doesn't smell like anything and the engine runs perfectly.  The smoke stops when the engine gets to operating temperature. I checked the oil and the coolant levels and they are fine. I can't see any coolant or oil leaks. Is this something I should worry about?  Could this be condensation?

It could be condensation, possibly compounded by the position of your mufflers. I think you said you mounted them back further. Try to check and see how long it blows white smoke. Hard to say in those conditions. But then it's hard to believe it's cold in Florida!
It might be solved with a simple weep hole drilled in the pipe in front of the muffler. Hopefully, it's not necessary and the temperature will soon straighten out. If it goes away as quickly as you say I wouldn't worry about it.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

do you have a heat riser on the left  exhaust manifold. if yea that is why you have white smokers left side is restricted so the exhaust will go to right under the carb.when the left side flapper heats up the spring relaxes and more exhaust  goes out left side

I recently blocked off the exhaust passages to the intake manifold.  Don't know if that affected anything?  No heat riser in my exhaust system.  2" pipes with two Magnaflows behind the X frame.   It's very humid here right now.  I believe what I am seeing is water vapor.    I'm running a continuously running electric fan and the engine is very slow to heat up in the winter. I just installed a switch to the fan and am hoping it helps warm the engine. At first I thought I may have a bad head gasket, but that's not the case. Thank God for small miracles.

I’m not sure how it would affect any non stock muffler but many cars of the 80-90’s had about a 1/8” hole in the center on rear for condensation to drip out. On my 56 here in California with my flapper replaced with a spacer and restricted crossover gaskets mine give some white in the winter. I also drilled hole in the rear exhaust pipe at a low spot before the exhaust comes thru the bumper and it always drips on startup. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Condensation will clear up within a couple of minutes of high idle speed, and unless you have a crossover pipe, the smoke on one side is indicative of a valve guide being loose, and oil draining down into the chamber when the engine is shut off for any amount of time.  A seal may be broken, stuck, or the guide simply worn, letting oil into the chamber.  If it clears up after the engine is warmed up, it is normal.  It takes a lot of oil getting by the guide/s to lower the level enough on the dipstick to measure.  It takes at least 15-20 minutes of high idle, or seven miles for the condensation to go away in cold weather.  Condensation inside the engine does not usually manifest itself in the exhaust pipes.  Joe-JDC  

JDC

HEAR IN THE BC CANADA ARIA BLOCKING THE EXHAUST UNDER THE CARB IS NOT SMART. if the flapper is removed some us different mufflers ,1 more restrictive than the other.  the water  is the least worry as with no heat under the carb over rich and un Burt fuel have issues down the road. hear more sever than warmer arias south