Wwest, it appears as though you have completely misunderstood the gist of this discussion, and have veered significantly from the original questions.

All the original poster wanted to know was what to do about all of the open ducting left from his heating equipment removal, and whether there was anything he missed. Gunter and Grady answered those questions very well.

The bottom line is, there is significant risk in running heat exchangers with no airflow through them. The original poster (and anyone else reading this thread) needs to understand that quite clearly.

My mistake, I was not clear here but what I am trying to say is keeping it plumbed will help with the air flow thru the heat exchangers and out the flaps when they are closed to the cab. Plugging it on both ends will not allow heat to escape/flow from the exchangers. Please disregard my comments about opening the flaps partially, I agree it does not make sense in this case.

When my temps go up in trafffic, I pull my levers up a little to activate my heater blower to help cool the engine down, even as little as it might be.

I have the fans you recommended and will be installing them asap. Thanks for that WW :D

If you have heat exchangers then air should flow through them, in other words then there should be no openings or holes around the back of the engine.

As for leaving the heat exchangers unconnected to the body, I have done so in some 911s that I owned and so have many of my clients because I used to live in South Africa where the heater is seldom used, if ever. It gets hot there. The lack of back pressure that I read about here has never caused overheating or excessive engine wear that we could detect. A friend of mine who used to work for Porsche in Dubai (where it is boiling hot, day and night) said that they didn't even fit heater hoses on cars there, again with no measurable effect on oil temp or longevity on the road or track.

I guess the lack of back pressure makes you lose some airflow over the cylinders and heads, but then again the extra air flow over the headers keeps them cooler and cancels it out.

Pardon, but I don't see that the design of the heating airflow valve's position will have enough significance on airflow back pressure to make a difference on engine life.

During HOT weather the valve's will likely always be in "dump" mode, virtually no back pressure.

Granted, since there is too little airflow to the cabin in heating mode that would mean a fair level of back pressure against easy airflow through the heat exchangers. But if the climate is so cold that you need heat there would be little issue regarding adequate engine cooling.