Unfortunately, with a 2.5 200 you are looking at a lack of torque on the bottom end. This means you have to nail the PVS openings to get the motor to wind up a bit to make enough horsepower to get out of the hole. The 3.0 block makes more torque down there, even though the 2.5 200 and 3.0 200 make the same total horsepower. The torque curves are simply significantly different. Once you get either motor up to the correct RPM, top speed should be the same. But the 2.5 block is simply going to have more trouble swinging the same pitch at low speeds. So you will need to comrpomise. If you want to run with the big block 200s, you have to swing the same prop, and sacrifice hole-shot. I never saw this better illustrated than in 1992 when Merc introduced the 2.5 liter 150 XR6. They also made a 2.0 liter 150 as well, but the XR6 would murder the small-block on takeoff, and on a heavier hull, it would out-run the small block on top-end as well. The small-block simply had to run less prop to be able to lift a big bass boat out of the water… while the XR6 could summon enough grunt to swing a bigger prop on the low end for hole shot, and then use the same horsepower on the top end to move right along. The old “there is no replacement for displacement” remains true…2008 Pantera Classic2014 Mercury Pro XS 200
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