I have a standard Toyota 1.6 4a 8v carb engine and was wondering if its possible to get more power out of it without compromising on reliability?
Not really. And I can answer that without asking what Toyota model or year. There has not been a 1.6Liter in a Toyota in the US for a long time. There are some things that can be done, but that cost is not worth the very small bump in HP and is not even legal in Calif and some other States, anything is 'tampering' and will not pass inspection. Sorry, there just isn't anything without doing exactly what you said, taxing the engine and transmission.