Just thought of a thing ive never read or thought about although i think i know the answer.

X-flows are oldish so there fore probably run on leaded fuel. Are they ok to run unleaded?? With or with out additive?

Looking at a 1984 Haynes for a MKII Escort, No. Would have thought you'd be able to have the valve seats replaced to allow you to do so though. Most likely the case due to the xflows popularity.

the heads aren't suitable for unleaded fuel. Burtons doesn't recommend LRP or additives, but they of course want you to pay them for work i.e hardened valve seats.

These are the best option, but do necessitate the removal of the head and valves, and can cost up to £200.

Regards,
Mark

Im running mine on unleaded with Millers VSP additive.
It seems to run ok and i will just convert the head when and if the seats become damaged.
Paul.

as you probly wont be doing huge millage,if you dony do long motorway runs it should be ok,there should be a coating of lead on the seats,unless you ground the valves that is

You will pay around £100 + VAT for an unleaded conversion, if you do all the mechanical work yourself, i.e. take a bare cylinder head to the machine shop.

It is worth taking it to a dedicated auto machine shop, as there is a fair bit of skill and art in putting the inserts in correctly. Mine was done by Scholars in Suffolk (reasonably close to where I live).

David