Engine choice was the KL-ZE 2.5 DOHC V6 making , a high-compression version of the KL-DE, or the KF-ZE 2.0 DOHC V6 making ; all of the K-series engines in the MX-6 were based on the same engine block and included those found in the Ford Probe, Xedos 6, and MX-3 V6 models. The KLZE had about 40 more horsepower than the KLDE versions for a few reasons. Although the displacement was the same, the KLZE had more durations on the cams, higher compression due to a different shape of pistons, and the intake manifold was different on the ZE. The KL-ZE intake manifold runners were shorter and wider than the KL-DE manifold. Also, the heads on the KL-ZE were ported and shaped differently. Not only was the ZE higher in compression, but it was also a higher-revving engine. The only flaws in the KL-ZE design were the weaker valve springs on the intake valves. This is usually corrected by using the KL-DE springs, keepers, and retainers which are stronger.