Starter for Frankenstein Project?

[TxCajun]

I'm having trouble finding a starter for my truck.

My barn find 1966 C10 Short Fleetside six cylinder with three speed manual was an old farm truck that had hodge-podge repairs over the years and is a bit of a Frankenstein.

I've rebuilt the engine (1973 to 1979 250 cu in), installed a new clutch, rebuilt the transmission, and have re-installed the drive train in the truck.

The truck came with a 3815891 Bell Housing which was broken in the area of the starter, and had some other cracks. I found another Bell Housing (same casting number) and installed it when rebuilding the drivetrain.

The truck came with a starter that had inline bolts for mounting to the block, but it no longer fits with the new bellhousing. I now realize that previous owner(s) must have busted out this part of the old bellhousing to make the starter fit because the cast nose of the starter won't fit in to the new intact bellhousing.

I tried getting a rebuilt starter that bolts to the three bolt holes in the bellhousing, but it won't engage the flywheel which is the smaller 153T (12.5").

Possible solutions:

1. Find the correct bellhousing that will work with the starter that bolts to the block. Anyone know what casting number that might be?

2. Install a 168T (14") flywheel if I can find one that is drilled for the smaller 10"/10.4" clutch.

3. Starter
a. Find a Chevy starter that will work with this bellhousing and 153T flywheel combo. Any ideas on what Chevy starter or application might fit this?
b. Buy a Mini High-Torque Starter. It looks like these bolt to the block, work with either 153T or 168T flywheel, but don't have the large casting nose of the Chevy starter that currently interferes with the bellhousing. Summit and others appear to offer some of these for about $120 so that may be the least expensive and quickest solution.

Any thoughts on compatible parts or solutions would be appreciated!