Maniac,
Trans Ams certainly ran 403s and were terrors of the street in the 80s.
Having said that, there are an awful lot of performance Olds people who would take a 350 over a 403...and do every day. For pretty much the same amount of money put into a performance build, the 350 will spin faster, last longer, and put out more horsepower despite the fact it's got 53 less cubic inches.
As I said, IMHO. And you know what they say about opinions....
C.J.
BTW, I'm really not trying to flame or fight. My posts sometimes read harsher than they sound in my head when I'm typing.