Depends on one's working definition of conservatism and exactly what set of values one wishes to conserve...
Some parts of the neo-con doctrine are quite conservative but you'd probably have to go back quite a ways in American history to find the kind of society that these folks envision. But one thing is fir sure, it would be pre-New Deal and possibly pre-Emancipation Proclamation...
Folks point out the radicalness of Bush's spending but it makes sense. Spend the government into near bankruptcy and then say "Sorry, we've spent a lot of monwy protecting you and now there isn't enough money left for those silly New Deal programs."