I need advice on my Fiat 600D's cylinder head.

I am having my engine overhauled. New pistons etc have been installed, and ready to go. However, the cylinder head, after sandblasting, and then pressure tested, leaked. I have been purchasing cylinder heads for my Fiat on ebay. I am currently on my third cylinder head - all leaked when pressure tested.

Frustratingly, I am about to buy my fourth cylinder head. Firstly, can the cylinder head be fixed? If so, can you recommend an engineering firm that can do the job.

Apparently, there is a leak in the chambers where the water circulates, and is close to the valves. The location of the leak (pin head size) makes it impossible to mend. Is that correct?

I have been speaking to Fiat specialists, and they say, the cylinder heads of the 600D were mass produced, and the quality hasn't been great. The heads are weak, and prone to cracking. Sigh!

Does anyone know where I can buy one that works?

An update:

I decided to bite the bullet, and get the cylinder head repaired.

I got in touch with Jim Stokes Workshop Ltd. They will repair it, including welding, new plugs, skimming, strengthening valve seals (for unleaded), sealing, and other modifications.

OMG, their workshop is amazing!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

There is a process called Vacuum Casting Impregnation

More info here -

https://forums.aaca.org/topic/162254-epoxy-pressure-porosity-sealing-cylinder-heads-blocks/.
https://www.godfreywing.com/blog/how-impregnation-makes-porous-parts-pressure-tight
http://www.surfacetechnology.co.uk/classic-car-restoration-impregnation-services/

The casting is chemical cleaned and then resin is forced in under vacuum. In view of the potential for hidden porosity, it's probably worth having it done on yours in addition to the engineered repairs.