the black top S13 engine and the S14 engine's are just about the same... except for the VTC and the different intake manifold. We put the S13 black top motor in the 97 240SX cause it's a cheaper engine and it's much easier to get. The VTC and intake manifold wasn't an issue cause we're gonna put on adjustable cam gears (which kills the VTC system anyways) and a greddy intake plenum which is like the S14 plenum but angled for better flow.