Bill, I have a lot of information on them and have a few parts left. The Simca version of the V8-60 has flat cylinder head combustion chamber areas and the block is relieved. The pistons are flat-top instead of the domed 60 pistons. The intake runners into the block are significantly larger in diameter than the normal 60 and the cylinder head gasket sealing area is slightly taller toward the intake manifold side. The intake manifold is set up for a single two-barrel four-bolt Zenith-Stromberg that flows a little more than a Stromberg 48. The exhaust ports are considerably larger than the 60 and are located differently on the block. There is a single water pump in a very different front cover that also contains the vertically-mounted distributor. Inside, the main bearings are the same as the 1940 Ford 60 block. The rod bearings are larger diameter than the 1940 60, are inserted and there is an individual bearing for each rod, no shared bearings as on a 60. The oil pump is built into the front main like a 60 but the pickup is up front and is integral to the pump cover. There is an aluminum crankcase extension that uses the same gasket as the 1940 60 with a steel oil pan. The camshaft is located in the same bearings that the 60 uses but the lifters are mushroom type, inserted from inside the engine, so the cam and lifters are not interchangeable with the 60. Valves and springs are similar to the setup on the 8BA. Early Simca engines are like the French Ford 60 with split valve guides and mushroom-stem valves but a '59 should be like an 8BA. The flywheel looks like a 60 flywheel but the starter comes in from the opposite side of the engine so the ring gear is reversed. The flywheel retainer bolts are drilled with a different pattern than the 60. Clutch driven plate has a differrent number of splines and the clutch cover is not interchangeable with the 60. So, what is a direct interchange? The main bearings, the 60 oil pan gasket which fits the crankcase extension, and a few odds and ends. Parts are very difficult to obtain, you will be researching the French eBay site and emailing French vendors. I helped a FordBarn member in New Zealand by selling him what I had left and tracking everything down for him that he needed in Europe. It took more than a year and a half of concerted effort to find everything. The prices of parts are obscene when you do find them. You will end up manufacturing a lot of parts that you could normally buy off the shelf or find relatively easily on eBay. There is a club in France that is not very helpful for Americans looking for parts and a very active club in Holland that bought up all of the parts that they could fine left over in dealerships in Holland and France. I can track down my list of suppliers if it will help.
With all of that, if your customer is willing to wait and to pay what it takes to build the engine, your experience with various Ford flatheads will make it easy to actually complete the build. The Simca has an amazing amount of power for those accustomed to the normal US 60 and it is a really nice engine when it is running. Stock Simca flatheads were rated at 75 DIN (European) HP, which is more like 85 SAE BHP. If you are interested I can put you in touch with the fellow in NZ who just completed his, and I have a video of it running.
I have a couple of intake manifolds, a crankcase extension and oil pan, a couple of heads - one damaged - some valves, exhaust manifolds and a lot of printed information if it will help.
Best wishes, Greg in Jax