@DanInSunnyFL could run 6/3 romex through the block wall instead of conduit. I don't know if inside the block of an exterior wall is considered a wet location, which would require UF cable (more expensive).
For a longer run I'd install a 6-50 (not a 14-50), use 6/2, and spend $35 on a 6-50 adapter. Neither the HPWC nor the UMC use the neutral. Once you get over 25 ft of wire, the cost savings for 6/2 pays for the 6-50 UMC adapter. The 14-50 is kind of dumb; it's a hold-over from the pre-supercharger days when people on road trips charged at campgrounds. Now we're stuck with it.
Although it may be hard to find an outdoor, weatherproof 6-50. Outdoor 14-50's are sold for RV use, etc. So you may need to go with 6/3 anyway...
For a longer run I'd install a 6-50 (not a 14-50), use 6/2, and spend $35 on a 6-50 adapter. Neither the HPWC nor the UMC use the neutral. Once you get over 25 ft of wire, the cost savings for 6/2 pays for the 6-50 UMC adapter. The 14-50 is kind of dumb; it's a hold-over from the pre-supercharger days when people on road trips charged at campgrounds. Now we're stuck with it.
Although it may be hard to find an outdoor, weatherproof 6-50. Outdoor 14-50's are sold for RV use, etc. So you may need to go with 6/3 anyway...