ANY of the tri-five vendors carry these for around $100.00 (ie Danchuk). They were originally made to adapt the early 265's (that had NO starter motor boss on the block) to later model transmissions (ie TH350/400/700R4). But, they can also be used with a broken starter mount boss on any sbc/bbc; you HAVE to use an early 3 bolt style starter that would normally mount to the bellhousing/Powerglide adapter ring AND a 168 tooth flexplate/flywheel..

 

I have heard about a horseshoe looking adapter for small block chevy blocks when the ear cracks or breaks of where the starter mounts. Can anyone tell me if and where one of these things exists.

Here's one of them: http://www.classicchevy.com/chevy-e...r-plate-kit-small-block-engine-to-turbo-hydra-matic-transmisison-1955-1957.html