Poor head design was the 6.5 Tecumseh. Animal block is not good? Compared to what, or in what way?
It's an industrial pressure washer motor not designed to race, so no it's nothing special and yes my clone will run all day and all year on methanol. I had one that had over 40races on it turning 8500rpms it was stock stroke with a stock bore honda piston($17), 308 cam $100, 1.2 stamped rockers (cheap), billet rod($60) and an old flat head tillotson free, billet flywheel $60 used with stock sized stainless valves in a 14cc head off a 5.5hp clone. Do the math hater, and it would smoke your animal all day like that. The only reason I went through it was cause I just thought it might be a good idea. Btw I'm a body man not an engine builder and I built it myself with a little common sense and a knowledge of tooling and fabricating and some torque specs. We used to race them up and down the street all day then take them to the track and race them so it actually probably had 100 races or more on it, just change the oil and tires and keep going.
I race UAS and own a real racing engine(fi jawa 500cc), so yes the briggs and clone blocks are crap, yea one is a better casting but they're still both not designed to race. If the clone is too cheap for you buy a honda block it's just as good of casting and the head is much better, I've got one that will toast built animals and I'll still have less money involved.