Take a guess where the bottle neck is!

I have a similar set-up with my 340, it runs out on top end also, but I currently have an Edelbrock 750 verses your 625 Barry Grant. I only bought my car this summer, so I have no idea on the times it would run.

You make no mention of your exhaust system, mine has stock manifolds (of unknown vintage) and a stock dual exhaust system other than Flowmaster mufflers.

I am switching to an Edbrock Performer PRM intake (the price was right otherwise I would have gone with the Air Gap). I have headers coming and plan on redoing the exhaust pipes also this winter.

And as the cam goes, mine is similar to yours...I am swapping in a Comp Cams "274" when I paint my engine bay.

I would beef up your fuel lines to 3/8" and double check your fuel pump is working properly.

And I would say you need more gear in the rear...I have a 3.91 in mine...that should wake things up a bit.

My 2 cents,
Paul