I have used them both on everything from mild street to much more serious combinations. I like them both, but I give the Offy the performance edge. (although I have ZERO head to head dyno experience to back it up.)
Here is a pretty nasty 462 I build for my '40 coupe.
And, a healthy 389 for my 51 Merc. I made my own air cleaner base to get around the goofy carb spacing.
-Abone.