[1963 corvette]

If you're talking no power adders and automobile racing I'd think one of those big inch Sonny's or Musi PM engines would get the nod. They're what - 2100,2200hp?

Sonny's we had didn't make 2000 na.Pretty close but not quite.

 

[1963 corvette]

I would say the Briggs vanguard twin cyl pretty stout.