The reason they suggest an 049 is that these engines have an integral fuel tank and are relatively easy to install.
Anything larger would require you to redesign the structure to accommodate a tank, plumbing, and some kind of access to it all. Also need to strengthen it for the increased weight.

By the time you’ve done that, probably the weight increase (wing loading) will be significant.
Not saying an accomplished model designer and builder couldn’t do it, but emphasis is on experience in such.

The rest of the delicate structure should also be carefully reviewed for its suitability to an ic engine.
Making successful ic flying models at these sizes is more difficult than the larger or giant size models, and today e power does seem more practical for them.