'65 GT Manual Steering Overheating? Take II

The steering on my '65 fastback seems to tighten up after I have been driving for a while. I noticed the problem after I bought the car. I had the original gearbox rebuilt about 2 years ago and it took all the play out, but it still tightens up after some drive time. I also rebuilt the front-end. I have two theories:

First, the gearbox sits right next to the exhaust manifold and gets screaming hot after I have been on the road. Anyone ever here of this creating a problem or the use of a heat shield?

Second, as the tires heat up they grip the road better and are more difficult to steer. The car has eagle GT IIs. I don't recall the size. They are a little wider that the original tires, but they are not overly meaty.

Any words of wisdom? Thanks in advance.
 
heat from the exhaust definately makes sense, even though I've never heard of anyone having that problem. My headers are all over the steering box on mine and I have no problems. It would be easy to fab up a heat shield and see if it helps.

I seriously doubt its the the tires heating up, unless you drive really really hard around sharp corners for sustained periods of time.

Interesting problem....let us know what fixes it.