You're already past it, but here's what you should have done. It's the same for most any engined.
Prelube engine by spinning oil pump with a drill until oil reaches the valve train. Put distributor in, start and immediately run at 2,000 rpm for 20 minutes, minimum. Keep an eye on the temp gauge, if it gets too hot have helper start misting the radiator to cool down. Don't slow down the engine unless you have problems such as loss of oil pressure or severe overheating. After that, reset your valves, torque the head bolts, adjust carb, points and timing. Then you're ready to drive. Follow my advice on up and down throttle to seat the rings, it works. For the first 1,000 miles go easy, no high revs, heavy loads, burnouts and the like.
I would recommend the break-in oil, the manufacturers put it in these vehicles when they were new. If not, go 10w-30. Change after 300 miles, then after 1,000 miles and again after another 2,000.
