[steelcomp]

In my experience you will have no problem feeding those heads. It dosen't sound like you much care about what happens below 2000 rpm. I would definately look into a custom grind roller, though. AFR is getting great flo no's with their given port sizes which equates into better port velocity over another head at the same size port. I don't think you'll need the (as much) split overlap that the 280HR has since the AFR's are going to be real good on the exhaust side, as well. The Performer RPM or Stealth will give you better throttle response and power below 2500, but you'll loose power where your heads (and appropriate cam) will really shine, at the upper range, say 6500-7500. If that's where you want to be, a single plane is better and the drivability difference will be slight, especially with a loose converter. I wouldn't be afraid to turn the RPM, given your parts, if you want the power. Lets face it...that's where small blocks make up for being small blocks...with RPM. RPM = more air, more air = more fuel, more air/fuel = more HP. You'll need a good carb, 750+, too. I'm saying all this assuming you'll run open headers when you're at the track. Mufflers and exhaust will slow things down a little, but there's some good exhaust products out there as well. Your package, with the right comopnents will make extremely good power and torque, and should be reliable enough for street use. Granted, it won't like 1500 rpm, but that's the trade off. The smaller heads won't give you near the power, everything being equal.
Good luck!