Confirm or deny: An ABY head will not work on an MC block

[UrS4boy]

I think the answer is an ABY (or AAN or ADU) head will NOT work on an MC block. I *think* the reasons relate to the water and/or oil passages.

Confirm or deny (?)

[driftin jo]

If I remember correctly you can make it work with a little mod, but yes it won't just
work as it is.

[twoqu]

Well the multi layered metal 20VT head gasket is an upgrade for the hydraulic head 10VT!
Thats sort of implies they would, or at least the important holes are in the right place.

http://www.034motorsport.com/engine-components-audi-i5-10vturbo-multi-layer-steel-headgasket-10v20v-hyd-p-113.html

[driftin jo]

The gasket will work on both, it is the shape of the block/head were the main water port comes up from the thermostat housing on the block were the shape mismatch is.

[porkkis]

They're basically the same blocks.

[driftin jo]

I may or may not be getting confused with an earlier version of the 10v block though
can't be sure now.

[driftin jo]

Yes I'm getting confused the 20v head will bolt to any 10v block I think. You just get low compression, if bolted to an mc1 it's about 6.5 to 1 and and mc2 is about 7 to 1

[twoqu]

The definitive answer will be somewhere on Motorgeek! The "ghetto" 20V turbo conversions are usually based upon the MC2 blocks and 7A heads.
If a 7A head fits then the 20VT must, allowing for the dowel removal mentioned!