All the sixes I ever messed with were a couple of 235s, and I always liked them; they have a certain "feel" to them, both in their response and their sound.
The company I worked for used Dodges and Plymouths for fleet utility cars, and a few of the smaller pickups; they all had the slant six in them, and when maintained right, they were very durable, if a bit anemic in their stock form, but they got used by every Joe and Jane who needed a set of wheels, and worked well. Now, the big Ford, that is an engine. I worked a job with a guy who built Fords exclusively, mostly off road and 4x pickups. He had a beauiful mid to late seventies 4x that had one of the 42? engines, and it was a runner. He changed that thing out for a 300 he'd built, and it was even better performing out in the country we worked in. It had a four barrel on a Clifford manifold, a cam that was definitely not stock, but was not real lopey, either, and a set of headers. The exhaust was the same he'd used on the 42? from ahead of the mufflers, back, a 2 - 3/4 inch system which was big for those days; it sounded very good, a really throaty rumble and growl, rather than the customary buzz and rap of a smaller piped six.