i think 250~270 is possible and a relatively easy goal to attain with those parts.
you'll be down a little power across the board because of the stock logs.
rethinking the cam might net you more torque lower down in the range and give better driveability/street manners. newer modern grinds take advantage of better lobe design and more aggressive ramps and if you combine that with a split pattern you can get some real decent performance from these smaller cams.
because it's a 69 motor, it's got decent compression. i wouldn't touch a thing in that department, that way you're not hemmed in on having to always run 91