if it doesn't say you can do it specifically, you can't
Really?
They've anticipated where each individual molecule of metal must be?
Every valve spring rate?
Every port shape?
Every fuel droplet?
See, that's the problem with attempting to suppress innovation: when you're right (you have anticipated all forms of evil), all progress stops, and you have IROC revisited.
Happily, this conceit (although popular) is a complete fiction, much like 1st Amendment law.
Let's dispense with moralizing for a brief moment: any "official" who thinks he knows everything that can be done has a very poor grasp of the subject, and an ego in inverse proportion.
Smokey made those people look pretty stupid for 30 years (found something they thought was off the table, and used it), didn't he (and to a lesser extent, Garlits, Moss, Widmer, Robinson, Taglioni)?
And they were sooooo p*ssed off every single time they thought "now, we're done - no wiggle room here", and he did it again.
I invite those who disagree to search prior posts for comments I made that (although may prove impractical, or not cost-effective) were outside the current rules - and were instantly met with "don't be ridiculous, everyone knows what that means", "no one would ever do that", "what would be the point", etc.
The problems remain:
1. the level of interest (both official and informal) in actually making rules that do whatever is believed necessary (exactly what they do is another question) is rather low.
2. the ability (as demonstrated by the existing rules) to form the intent into language suitable to make the rules both understandable (remove all but the 10th percentile of "is this legal" questions) and enforceable (same effect every time, no exceptions, no subjective interpretation) is even worse.
Don't be depressed - Congress can't do it, and the Supreme Court is only slightly better.
SCTA rules could be dramatically improved with only minor changes of language with no effect on current records - if the will be present.
