Living with a 2.21....

Everybody saying to swap in an overdrive... yeah. That's a LOT of work. Not saying it's not worthwhile, but it's a big project.

I would get 2.71 gears with the sure grip. I would also swap the intake for a ported SP2P with the long skinny runners. Your intake has a relatively big plenum volume and runner cross section for that engine. It puts your power band much higher in the rev range than your gearing will allow.

I have a 4bbl factory ported intake and 600cfm Edelbrock and I think that's really overkill.

Hook up a Tach and watch how much RPM you're turning when accelerating and when cruising down the highway. I bet it's not even 3000rpm. Hell my 5th Ave with 2.21 gears barely breaks 2000rpm. Then go ahead and punch in your numbers here:

Wallace Racing - Intake CFM Requirement

Tell me how many CFM you really need.

What you really need is port velocity. I'm willing to bet a high flowing intake like that has got some really lazy ports on this combination. It would be different if you were turning 4000 or 5000rpm but that's not the case, it ain't a manual transmission 1/4 mile car, it's a slow revving cruiser. Gotta design the combination to match that.