Seeking Make & Model of the following engine.

I'm going to guess that it was not originally built as an RC engine. But is a conversion from a leaf blower or some such. Just a feeling I get from the pictures though I could be wrong.

yup, that mounting plate kind of screams conversion. an engine designed to be an airplane engine would have some sort of conventional mounting provision designed into the case, or come with a mount that is designed to work with that specific engine. the carb spacer and throttle linkage give it away, as well.
given that it is a conversion,...whomever did it , did a decent job .....i'll say that !.

You might try reposting here GAS ENGINES

Real petrol head hang out.

I agree with the folks above . It was probably done in the late 70's or 80's and it may be a " ROSSIE " Red