340 vs 340.

Decades ago Direct Connection had a list of their performance big block cams and ET results in the same 400 engine. Don't know where to find it. The differences were small increments, but improved as the cams got bigger. I don't recall the steps being much more or less than .10. (No radical, race only from what I remember.) But your "port cleaning" may overcome that. The lower first gear would also be an advantage as long as it didn't cause more wheel spin and the engine had a torque curve that would recover better from the 1-2 rpm drop.

Too bad you haven't been to a track. 60' times would mainly show how good the suspension & tires work while MPH would mainly show the overall HP.

Overall vehicle weight is also a factor. Weight distribution comes into play and sometimes adding weight to the back will reduce wheelspin enough to overcome the added weight disadvantage ET-wise. (...and add a little consistency for bracket racing.)

As pointed out, tune-up and driver ability would likely be the biggest influence on the outcome.