Hi,
I do feel for you. Finding damaged pistons must have been a bitter disappointment.
I have no direct experience of the 8140,27 engine, but I did own a 2.5TD Talbot Express for about 15 years.
The 2.8JTD, 8140.43S, is a developement, of the 8140.27, and was also used on the Iveco Daily.
On the 2.8JTD, vacuum pump, oil pump, oil cooler, oil filter and steering pump are all mounted on a sub assembly.
Instructions for dismantling the sub assembly, only mention unbolting and removing the power steering pump, but with the sub assembly already removed from the engine.
As the power steering was an option, it would make good engineering and commercial sense to have only only one design of basic sub assembly to which the steering pump was added when required.
May I suggest that a carefull examination of both old and new engines could resolve this. It may be that your old engine has a blanking plate which could be transferred.
Sorry that I cannot be more definite.