As was mentioned, living in a cold-climate region is a consideration; however, the Mummert aluminum intake manifold has no heat crossover. If you don't live in a cold-climate region, or do not drive your car at/below near-freezing temperatures, I don't think you'll have reason to be concerned. On cold, not freezing days, it might take a bit longer for the engine to reach normal operating temperatures. Regardless of the crossover or type of choke you might have, running the engine for short periods of time without it reaching normal operating temperature is not a good thing, no matter the make, model, or age of vehicle (unless it's an EV). 

As for condensation in the exhaust system, that is natural, (especially in high humidity areas) if not driven long enough to heat expel it (all short trips - little heat).

Do the service replacement mufflers have weep holes drilled?

Does yours have bumper exhaust outlets?

As for the heat riser valve itself, there would be no difference if mounted on either side (duals).

The way cataloging reads - FYB

1955 FORD - ?
1956 FORD - RS
1955 BIRD - LS
1956/57 BIRD - RS

Everyone run out to the garage and report ...

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"Does the crossover heat tube need to be blocked off if it is not rotted? Mine was a stainless replacement that I pounded in years ago."

No. As long as the tube itself is intact, there will be no exhaust leak (if the manifold crossover tube openings have not been wallowed).

Now here is the problem. If one defeats the heat riser valve, there will be very little hot air (exhaust crossover) under the intake manifold carb plenum to atomize the fuel charge properly and also the hot air choke draws the heated air from that source (via the crossover tube). The choke may not release fully or be slow in doing so. The heat riser does more than just provide hot air to the choke. 
 
All of this also depends on where you live and what weather conditions you experience. While the ambient temp may not get very low, the humidity may be high and possibly lead to icing.

FORD installed this system(s) on most cars so it would be drive-able under most any condition.

Choke settings were usually adjusted for winter and summer operation. The heat riser valve itself was also lubricated with a special lubricant to keep it from hanging.

What gets me is the RS inlet pipe hanging low. Did the vendor offer a choice of pipes, one with the valve and one with the valve removed?

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Does the crossover heat tube need to be blocked off if it is not rotted? Mine was a stainless replacement that I pounded in years ago.

The 55-57 Tbirds have the heat-rider valve on the right/passenger side; the choke is on the same side, whether it's for a Teapot carburetor or 57 4150. Even if you have a full-size, it doesn't make sense to me to have the heat-riser valve on the opposite side of the choke. I have a modern carburetor/w electric choke & Sanderson headers. The ECZ-B intake manifold heat crossover is blocked as well. 

I replaced mine with a spacer, but if you are having problems with the pipe hitting you can get rid of it.  You will have to thread the stud down further or add spacers  between the pipe and the nuts to make up the un-threaded space.  The studs usually are not threaded all the way down when the valve was used.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

There’s a time and place for the heat risers, but I haven’t had one on any old vehicle in years. They all got headers. So just put yours back as needed to stop the rattle. Any engine will have a muffler rust problem if they aren’t driven far enough to warm the whole system. Takes heat to cook the moisture out, and even in stainless system you can plug up the packing if it’s that design.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I wonder if it makes any difference which side. I am still leaning towards removing the one that is currently on the right side, thus raising my exhaust pipe fpr more clearance. It would allow both sides to blow out condensation on cold mornings. Glad I ordered stainless pipes when they were affordable. I am on my second set of mufflers. These cars are hard on exhaust systems.  Just an after thought: The fairlane models had the teapot 4 barrel with the hot air choke using the heat tube in the intake manifold.Could be that this specific set up required the valve be on the right side.

OK, hold on a minute ...

I re-checked cataloging and there are two ILL's for DUAL EXHAUST. One ILL reads 1955/56 FORD DUAL 'TYPICAL' and is the one I posted showing valve install on the LS. A few pages down, another ILL is shown titled 1956 FAIRLANE 'DUAL EXHAUST'  and shows the valve on the RS. 

So that is my mistake. Your install appears correct.

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Looks like from your picture that I have been running mine on the wrong side. Mine is currently on the passenger side which might explain the low hanging exhaust pipe. I wonder what I have hurt by running it this way. My car had the thunderbird V/8 option and still has the original manifolds. Exhaust and tail pipes are stainless and were ordered from Concours years ago.