Almost anything can be bought. That said, a shop would go broke rebuilding B230F's as a product offering.

Since it is niche market with microscopic demand, start with ebay or a volume Volvo recycler like Revolvo or the one out of Atlanta whose name I can never remember.

Not a complex motor and NO specialty tools to rebuild yourself (except a piston ring compressor and valve spring compressor). Most machine shops will do the heavy inspection work for you for nominal fee.