Hi Dave,
Something I tried last summer that completely removed the steering "wobblies" (in addition to the needle thrust washers on both main and rebounmd springs) was a (temporary, now permanent) diagonal 1/2" aluminium box section between the right hand front of the chassis and the left corner of the chassis at the rear left corner of the engine space. (My car is left had drive if it matters).
The wobbling was not as bad as I have heard some people describe, but it was there at about 40 mph. (Now it is not).
I felt that the front section of the chassis might be wracking in response to the wheel wobble, sort of feeding on itself once it started.
Since the wobble disappeared immediatley after installing this brace this seems likely. It would not need much of a wracking movement to start things going in a sympathetc oscillation fashion.
I have already cut and will soon instal a 1/8" aluminium sheet covering the bottom of the engine space and bolted to the chassis at three locations each side. This will stiffen everything enough to stop wracking and still allow chassis flexibility.
A + _ 6" hole under the engine oil drain plug will give some ventilation.... May even make a round cover with two retaining screws for this if ventilation is adequate with this opening closed..
There should be plenty of louvers for the cooling air from the radiator and engine space to escape.
A slicker underbody surface will almost certainly make for less wind resistance, perhaps quieter and less under body turbulence.
This mod will not interfere with any of the visuals of the car, and can easily be removed for shows etc.
david
