Oil pumps between BB and slant are completely different, although they are both externally mounted.
I picked up a BB gear drive with the same intentions, to see if I could mount it on the slant. I never found the time to try it but it certainly looks doable. You will likely need a cam stop to keep the cam from moving forward without the chain to keep it in place.
Keep us posted.
I already have the cam button figured out. Got one on the way. But, it's really not necessary. Not only does the slant six not have a camshaft thrust plate, but since there are no roller camshaft cores made for them, that means all we have are flat tappets. Flat tappet camshafts are tapered on the lobes. Not only does this make the lifters spin in their bores, but it also acts to push camshaft back into its bore and keep it in place. Lots of engines don't have camshaft thrust plates and they are just fine. But I do plan to run a thrust button anyway.