If you want to try heat shields, there are a couple principles to keep in mind. The goal is to isolate both convective (movement of heated air) and conductive (touching the heat source) thermal paths. The inside heat caused by the exhaust system is an example of convective heating and the gear selector housing heat is an example of conductive heating.
The most effective way to isolate a thermal path from the heat source to your body, is to place a shield between the source and the body without touching either of them. Clamping shields to the exhuast pipe will help somewhat but you are heating the thermal isolator. That is not a good thing.
I believe it is possible to optimize a thermal isolator by placing a piece of sheet metal on top of the frame rails and continue running it up the toe board as far as possible. This isolator may be clamped to the frame using the same scheme as used for attaching the hood scoop block off plate. On the drivers side it can be run up to the underside of the master cylinder and clamped to the steering column. On the passenger side, it would be attached to the frame in the same manner and the top could fastened to an outrigger bracket mounted to the underside of the heater duct. That is probably the optimum as far as thermal design is concerned.
If you still want to clamp baffles to the exhaust pipe, you might want to try the following: '55 Chevys with power steering had Shield Assemblies` mounted on the exhaust pipe to protect the power steering hoses. Their part numbers are 3715008 and 3715004. I believe 3715004 is the longer of the two. These items should be available from most tri-five chevy parts suppliers. Just because GM did it, doesn't mean it was right. Remember, these are the same folks who had fuel filters and oil filters as options in '55.
Keep Cool, Tom
P.S. The baby birds have a couple examples of reasonably good thermal isolators in the engine compartment. One of the most obvious is the master cylinder "drip pan". You wont find this item on passenger cars. Another example is the sheet metal piece next to the battery. The Y-Blocks have heat shields protecting the spark plugs too.
[ 01-10-2003: Message edited by: nomadbird ]
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