A well-tuned, naturally-aspirated streetable gasoline engine with 2V/cyl will have a BMEP at peak power in the order of about 10 bar and ~12 bar at peak torque. Your criteria of not wanting "to work the engine as hard" probably means you want to keep the revs and BMEPs down. 5500 RPM @ maximum power with redline about 6000 RPM seems reasonable along with the above-mentioned BMEP values.
With those assumptions as boundary conditions, I calculate a displacement of 7.3 liters, or 445 cu.in. Yeah, seems like a lot, certainly well into BB territory. Naturally, by optimizing the compression ratio and timing for alcohol-fuelling, you can increase the BMEP or conversely reduce the necessary displacement to achieve your horsepower goals, but don't be unrealistic; figure on maybe 15% at most.
Naturally, you can build an engine that gets much more than the ~1HP/CID displacement calculated above, but then that gets out of what I would define as a "not hard working engine." Cams should be mild, and ports should be well-shaped but certainly not oversized for the expected HP range, and use compact combustion chambers without excessive valve shrouding but properly placed to maximize charge motion. Static compression ratio can be around 12:1 as a starting point with flat-crowned pistons. A very high-energy ignition system would be necessary to reliably ignite alcohol/air mixtures. Keep in mind that stoichiometric AFR is ~9:1 for ethanol and only ~6.4:1 for methanol. Perform all cals at stoichiometric first before venturing out to even richer mixtures.
The lesson still holds, there's no substitute for cubic inches.
. Mean piston speed at 6000 RPM and 3.5" stroke (88.9 mm) is 17.78 m/s. At 5500 RPM, it's 16.3 m/s. Is that high? In the scheme of performance engines, not in the least.
