Bit of both really, lol. if you visit morrislubricants.co.uk they will have all the info you need for lead replacment additives. Another big thing in Engines is oil additives. ever heard of SFR?
Hi, the best product you can use on leaded engines is the MORRIS ZERO LEAD. I am currently a distributor for Morris and sell at some of th elowest prices in the uk. Ebay number 270164773274