Unless you're going BEC for ease of engine/transmission packaging. Or the lighter weight of a bike engine to allow you to tack it on elsewhere.
Personally, I'm kind of liking the idea of getting one of the new honda goldwing flat 6 engines for a number of reasons.
Decent power. Car-like torque amounts and curve. Same power and MORE torque than the miata 1.6 or a toyota 4age 1.6(not counting jdm silver/black tops). The bike is 900 lbs. So no worries about it holding up to locost use.
Flat 6-so low center of gravity, and a balanced engine. So less vibrations. Just because it's minimalist doesn't mean you should have to suffer. Just make design choices for the car you want.
Since there is no transmission tunnel. Which will allow me to have a bench seat, so I can pull the girl close to me on leisurely drives
. And just take out the bench seat and stick in racing buckets for autocross/fun drives. Can close off the engine bay a bit more as well, for more triangulation.
Reverse. Although honestly, that's a plus, not something I'm looking for. If I can push around, and steer a 2700 lb car on level ground, I'm sure I can handle a locust at half the weight, and easier to push(roll bar>door frame, locost weight distribution>car needing power steering with a 500+lb engine over the wheels). But it'll make my girlfriend, parents, and sister more comfortable in the car. And they're gonna drive the crap out of the car as much as I am, most likely.
For a bike, it's a heavy engine-just under 300lbs, fully packaged with accessories, transmission, and fluids. I doubt you're going to get a car engine under 450lbs. But given the output of the engine, that leaves me plenty of room to put in a cd player, and possibly even A/C. Dunno. Haven't looked into the A/C heavily yet. I live in South Texas, I don't need a heater. A/C would be awesome. I was a music major for 3 years. I need my music, 'intake/engine/exhaust noise is music' be damned, I need my Mendelssohn.
So using the goldwing engine allows me to build a car with the amnenities I want, drive like a car, but not end up a morbidly obese locost. Just a BEC that drives and weighs like a car engined car.
I'm not too fond of the two valve/cylinder design. Kind of limiting. But putting some individual throttle bodies and a better exhaust, possibly cams and some headwork, should squeeze out some power.
Plus you could actually size the length individual throttle body system properly, and not be constrained by packaging as much.
If I decide I want the power, and rewire everything. My current car(88 honda prelude) is a 16 second car. I've driven the same chassis as mid 15, low 15, mid 14 and low 14 second cars. If I do go the goldwing route, I'll probably end up with a 13 or low 14 second car. Which is enough for me to have fun in.
But admit it. Seeing 6 velocity stacks sticking up from individual throttle bodies would be sexy