Well it's a much nicer engine than a Tecumseh Red, it's just a matter of getting the installation right. Is one of your bonnet mounting screws too short? Looks like the bracket it's holding needs its corner filed, too.
The main issues I'd be concerned about are making things clear each other rather than rattle against each other, and supporting the muffler where its weight is, rather than having it overhang a long way from the flange mount at the exhaust port.
That's a good mower and an excellent engine. It's up to you to make it a good installation, so you get full benefits from the change.
