what size 12 point bit do I need.
its larger than and m6.
im guessing around m10.
my engine is an 84 and im going to pull a cylinder head from a 1985.

The older m110s use a hex of 10m, so that size is probably the same for the 12 point. Keep in mind that the shaft is 4in long for reaching the bolts in the valleys and of course it should be 1/2 in drive. I think Pelican Parts has this tool. Also investing a little in the MBZ valve adjust clawfoot tool is well worth the money.

__________________

Don't Chrome them; polish them

I suppose that you don't have the service manual for the engine if you are asking for tool sizes.
It not very wise to mess with an m110 without the manual. Also, a single socket WILL be the least of your problems: there will be slide hammers and other special tools too in order to take the timing chain out.
You can find the manual on the web for not much.