Try a "427 Ford" search on ebay. I see lots of old mags and some reprints available. Maybe contact a few of the vendors there and see what they have. The old mags seem to be priced between $5-14 depending on the issue. I have boxes of old HotRod's and such packed away from the 60's and 70's. If I can get a chance to get at them I'll see what there is.