First 318 build, cam question

I'm doing my first build, and I'd like some advice. The car is a stock '72 Swinger with a 318 2bbl (not running), 904 trans, power steering, power brakes (front disks), and I believe the rear is a 7 1/4" with a 2.76 gear, but I need to double-check it. I have an old 600cfm Edelbrock 1406, matching air cleaner, and a new Edelbrock Performer intake that will be installed on the engine. I will probably install headers and full dual exhaust, but not until after I get the car running again. I don't know if/when I'll get around to doing any head work or changing the rear differential (I'm planning to do as much as possible myself, and I'm just an amateur with hand tools and a garage). The goal is to make a fun, reliable driver that keeps the power accessories - I'm not planning to race or show this car.

I was looking at cams, and saw the recommended one for this combo is the Edelbrock Performer 2177 (http://www.jegs.com/i/Edelbrock/350/2177/10002/-1) with .420/.420 lift and 270/270 advertised duration. There were others that say they work in roughly the same RPM range that advertise noticeably more lift, and several were dual-pattern, like this one from Comp (http://www.jegs.com/i/COMP-Cams/249/CL20-221-3/10002/-1) with .447/.455 lift and 256/268 duration. That Comp cam (and a couple others) are also available as full kits with timing chain, gears, and valvetrain pieces - I was thinking about getting it all at once to really freshen up the engine but without getting into the bottom end or trying to port the heads at home. So given the air flow restrictions, highway gears, and keeping PS/PB, how much cam is too much? Recommendations are welcome and appreciated - thanks in advance