The parent company is Kioritz but in the USA they are ECHO.

Shindaiwa is part of Kioritz or at least they merged one way or the other.

It might be a 520 and not the 510?

It is not current production. All the current 50cc engines have the separate cylinder/crankcase.

I have a BME 50 - they are nice 50 cc model engines.

I agree it would probably be better to buy the 1050 short block.