I have a mod sbc 350 with ported heads,stepped up cam, intake,exhaust,carb which was rebuilt fresh last winter. I pulled the drain plug for the oil for winterization - metal sludge on the magnet!!! Oil preasure is good - What to do???? Motor was properly broken in.

was the oil chaned since breakin?

Cut open the filter and see what's in there. Look for bearing metal (non-ferrous), bronze, or ferrous metal. If there is a lot you need to get into the engine.

I threw the filter out. Yes, the oil had been changed after the initial break in.

By chance did you save any of the oil even a couple of ounces? If so an oil sample will tell a lot, high ferrous is common during break in. Also just how much was on the magnet, for the first few hours a fair bit will show up. If you have a flat tappet cam and hard rings that will show of more debris than a roller setup. If there is any doubt what so ever pull it and get the pan off and check things out, if there is a problem it will only get worse. I am a firm believer in oil samples which are inexpensive and very conclusive, I start at 10 hours then at 50 hour intervals or seasonal changes which ever come first. This way you develop a history and use the same firm for sampling.

Phil