I would suggest to rather shave the head.
If it does'nt work out the way you want it, you can replace the cylinder head with another one.
If you deck the block, well, you will have to replace the block.
Less effort in replacing the cylinder head than the engine block.

9:1 in standard A12 and 10:1 in A12GX

whats the standard comp ratio for an a12

Yeah measure the combustion chambers.(well you only need to do one)

Wait untill dattoman1000 or converted(or someone else with racing engine building experience) comes on they'll come on they'll know how much to take off.

so is the general consensus that 80 thou of the head would be the go to get 10.1 comp. Has anyone else shaved their a15 head and know how much to take off? Also is there anyway of checking if my head has been shaved previously? as i dont want to shave it again if it has! is there some measurement that i could do to check this?

i milled .070" off my a15 head for an engine running gas vapour injection, nearly 10:1 running 32 deg. total adv. and very happy.... dont get too gready with comp. only take enough off the block to acheave a clean flat suface, 5-10".

Well if someone said 80 thou that sounds right.

You'd have to do the math on it.

Yes you should shave the head not deck the block.

hey
I have just pulled my a15 down and are about to commence my rebuild. I have twin 40 dellortos, extractors, fairly aggressive cam but i need to know whether to deck the block or shave the head to acheive my desired 10.1 compression? I am keeping the original pistons and have been told shaving the head 80 thou will acheive 10.1 compression, how much would the head need to be shaved?
cheers