I'm currently using my third shop built wood splitter. It's also a horozontal/vertical model built using a trailer axle with 14" Ford wheels. It pulls nice on the road using the larger wheels. I bought all three engines (and a few more, too) from Smallenginewarehouse.com. I use the Honda 5.5 HP vertical shaft ones, and they work well. I've fabricated all the pump housing adapters from angle iron and plate. The valve I have on my current splitter locks on when splitting, and I have to hold it to return. I bought a new valve and an 11 gpm 2-stage pump (eBay), hoses (local), 4" x 24" cylinder (Tractor Supply), and coupler. Everything else was repurposed from something else such as the beam, tongue, LP tank from a BBQ grill converted to the hydraulic tank, etc. One of the ones I built and sold had polished 14" aluminum wheels, one had 13" Honda wheels, and this one has 14" wagon wheels. I have just over $600 in a splitter that would cost around $1250 ~ $1900 at Home Depot, Lowe's, TSC, etc. The ones I've seen using the same size engine, pump and cylinder are rated from 22 to 27 tons. I just know it will split 30" hickory with minimal strain, so ratings aren't that important to me. However, if I ever build another one, I will go to the 16 gpm pump for the extra speed on the return stroke.