WHOA, those specs are ONLY FOR THE S-25 NITRO ENGINE, you will destroy another engine if you use the same specs, every engine is different, so you will not be able to perform precision porting unless you can find information (timing, etc.) for your specific engine. You can do basic things like smoothing and polishing areas to increase flow, and you can do some of the other things, but you should NEVER do any port modifications without knowing exactly what you are changing and how it will affect performance. And no matter what someone says, never do the old "port matching", (matching the sleeve port with the crankcase, this will make your engine run like crap, or not run at all.) You can get general information about port modification by reading things like the RCCA articles, they have had the s-25 article, and a modification article for the traxxas pro 15. If you just have an engine sitting around, that is collecting dust and you don't care if what you do to it totally messes the engine up, go for it, but if you cannot afford destroying your engine, do NOT TRY TO PORT/POLISH.

By the way, what kind of engine is it, i may be able to help if it is one I have experience porting before.