During the disassembly of the M104.981 from my 129 I discovered that the block is damaged and can not be used. After I cried a little an idea came to mind: I have a low mileage M104.990 from a w140. Id like to use the block from the .990 while keeping the KE-jet in place using the .981 head and intake manifold.

I've done some research and this is what I found:

1. I will have to use the M104.981 oil pan in order for it to fit in the 129 thus I will have to use the .981 oil pump as well

2. I will need the M104.981 water pump as the .981 head does not have the front cooling port

3. I will need to use the .981 timing chain.

Now,

Assuming the head will bolt to the block..

Which headgasket to use?

I will appreciate any input