I would like to second what Mr. Watts has written on performance enhancement
using the technologies of the 80s and 90s. He speaks for a number of folks
like me who retired from SCCA racing in the early 70's and returned to
"vintage racing" in our dotage only to discover a number of interesting
performance anomalies that never were allowed in "real" racing in the 50-70
period -- like 1400 Bugeye Sprites, 911s that sounded like V8s, and
"formula" cars which represent their formula in name only.
I am, however, very sympathetic to the sorts of frame, axle, spindle and
wheel mods that keep the wheels from falling off. Most of these were
permitted in the period, at least by the mid to late 60s, when some stickier
tires started to come on to the market. Minus the tires, these sorts of
mods do not make the car go any faster, just safer.
Mad Mollusk Racing