Haven’t received parts yet, but bought a complete lot of high-end aftermarket small block heads, blocks, intakes, and stock blocks, etc. It was a good deal so I didn’t hesitate to pass it up, but probably should’ve asked more questions.
Well with the information you provided...
Do some of the small block parts interchange with each other?
Yes.
Intakes could be modified or use spacer plates to work from block to block type?
Yes, some could be.
How many types of intakes or heads are available?
A lot.
I deal with mostly big block or HEMI stuff.
I see either a fire sale or much education in your future.