Hi all just in the process of rebuilding / restoring a mk2 escort. Decided to get a 1600 crossflow engine to replace the 1.1 as it must have been stored at the bottom of the english channel. Before bench testing it i gave it a quick clean down and noticed a B stamped into the head above the exhaust port (front of engine closest to fan). Im trying to work out of this could mean it will run of unleaded fuel and has had the valve seats done. The engine runs sweet for the amout of time iv ran it but dont want to damage the seats.

Am i just been hopefull that i dont have to remove the head or is this a good sign.

Thanks in advance