If you take more then just Republicans and Democrats into account then Liberalism wouldn't be 'left' and Conservativism wouldn't be 'right'. The terms economic liberal and economic conservative are only opposites if you oversimplified the political spectrum into one dimension to fit the American model. Political matrices however tend to be two dimensional.
Liberalism strives to as much personal freedom and economical freedom as possible, while recognizing the need of some sort of goverment. Conservativism aims for a more traditional society, so with less social/personal freedoms, but they also hold economical freedom in (the same) high regard. So liberals and convervatives in the traditional sense both tend to perceive levelling incomes and building a huge social state as counterproductive.
The textbook answer would be that the difference between liberals and conservatives are purely between social/personal freedoms and actually have nothing to do with economic freedoms.
Democrats however, tend lean a bit towards the left on economical issues (towards Progressivism) then Republicans, which moves them a bit away from true Liberalism. I do believe both parties are about equally as far away from true liberalism, as they are both liberal in different aspects.
It's easy to argue that they are both quite liberal, as both parties seem pretty close to eachother compared to mainland European political parties. Both Democrats and Republicans are quite far towards the right. Democrats and Republicans are actually both so far to the right that they have no Dutch equilivant.
Depending on what you use as a reference they could end up like
*this* in a political matrix.
I'm not sure if I answered your question with this, as what I said seems a bit basic high school material to me. I almost feel silly for posting it.