These entry level small-block Chevy crate engines are ideal for any street rod, muscle car or truck owner looking for over 300 horsepower performance on 87-octane fuel They are completely assembled and valve adjustments are done . we offer them in one or two piece rear main configurations . they are equipped with brand new aluminum heads and 1.5 comp rocker arms. A return core is required , a core charge or $350.00 is required upon shipping.