Personally I would not trust a "GOOD" used cam, They are not too expensive to buy. I bought mine from Brands Hatch. Fast road cam, follower and spray bar. Delivered for £225
https://www.ebay.co.uk/itm/Ford-Escort-RS2000-Cortina-2-0-Pinto-BHP30-Fast-Road-Camshaft-Kit-ChillCast/122345481226?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649