400m (it isn't a clevo) run standard big block Ford bellhousing. There are Top Loader bellhousings, and Auto's in FMX, or C6. There is some "rare as" C4/C10 bellhousings, but they are hard to find in the US, and will need to be shipped out. I ran C6's behind both of mine.
There were some rare as 400m blocks with dual bolt patterns, small block and big block.
Is your mate going to fit this to a car that had a clevo in it?
Mounts are different, and his extractors may not clear the floor anymore. It will be quite tight in the engine bay of a Falcon too.
IIRC main bearings are 351W, inlet manifold gasket and manifold are unique, the rest of the gaskets are clevo. Pushrods are unique, as are conrods, pistons.
If your interested, I am clearing a bit of 400m stuff, single and dual plane manifolds, inlet manifold gasket and steel tray, plus a machined block, with resized conrods, fitted with new pistons & ARP bolts.