2 replies to this topic

[Monkeh]

i have a 12g940 head and was wondering if its an mg metro head?? as ive heard the mg has 35.?? mm inlet valves but my head has 33.?? mm inlet valves. thanks

[Turbo Nick]

the leaded mg head had 35.7 inlets, whereas the unleaded mg head had 33.? inlets, as did all other 12g940's.

[Dan]

It is basically impossible to tell from any 12G940 head what it was originally fitted to (except for Turbo ones, they had a T stamped on them at the foundry but even that could be done by anyone at any time). 12G940 is just the pattern number for the bare lump of iron that emerges from the foundry and it got machined into many many different large bore A+ heads for many different uses. Sorry.

It essentially doesn't matter what it was from though so long as it gets machined the right way for what you want, they all started out pretty much identical and so can all be machined to pretty much the same spec as each other.