Pontiac (and, apparently most or all GM) starters bolt to the block. I am doing a non-traditional engine swap into an FGF requiring a bell-housing mounted starter, as my block has no provisions for starter mounting. The bell-housing and flywheel are custom pieces which can be adapted to the starter.
Which Mopar or Ford starters mount to the bell housing?
What non-traditional drive train are you using? Are you using both the engine and trans, or are you trying a different engine to a Pontiac trans/clutch?
Might be easiest to use the starter that matches whatever ring gear/flywheel you're planning on using to ensure correct meshing, mech. advantage and current draw. The stock ones are not too expensive:
The non-traditional swap is a MB W120 DOHC Aluminium V-12. The trans will be T-56, either backing the block or from a C5. Hydraulic clutch (probably a Center force dual friction) will simplify linkage issues. Probably too much trouble to adapt the AMG 6-speed to the V-12.
I'm going to draw the line at chassis fab, so I doubt I'll go to the trouble to adapt the C5 3rd.
The bell-housing and the flywheel will both be custom made, but my preference is to use an existing ring gear for the flywheel. Plentiful options for ring gears are mostly US-made.
Located a Mopar hi-torque mini-starter and a SFI-flywheel. These look to be fine for the job.
The motor was an accidental acquisition and the body was someone else's failed project. It came with the trans and a BOP pattern bell housing for the T-56. Oddly enough, it's a cast & machined bell housing, not an adapter. It's not much good for the MB block, but some of the dimensions are helpful. The hydraulic clutch linkage also looks useful.