I'm not nearly as well versed in nitro as I am electric but I think any small block engine should fit. That being said make sure the mounting dimensions of the replacement are the same as the original and make sure the cooling head isnt too much bigger than the original or else you may have to...
You'll have to pull up both sets of exploded views and buy all the nitro pieces that the kit doesn't have like the chassis, engine mount, tuned pipe, etc.