build strokers or buy them

i think we go apart at your $3,000 top end
$2,000 heads and $1,000 valvetrain is just not in my program
take your $2,500 shortblock and put a $500 top end on it and we have a $3,000 motor
yes, an engine is an air pump and those $500 heads will squeeze that motor like some visegrips on a pair of nuts
but again, not everyone's program is balls to the wall trying to eek out every morsel of HP of an engine
an some point the return of $$$ on HP gains is slight and very costly.

Take my $2500 short and stick $500 heads on it and you'll have valves hitting pistons and oil being sucked down the knurled guides...lol. My point is - it's not "hunting for every morsel of horsepower". It's about performance. I do not consider horsepower to be exclusive. Higher horsepower comes from a higher efficiency, which comes from quality parts and precision machining.
In terms of heads and costs - the valve job alone for me is $500. That's because if you compare the quality of the work, the additional machining actions that are included that other shops may not, and the equipment and staff that does it there are dramatic differences. The guy doing them is a friend of mine who's been doing heads since the mid 80s. He works on a Serdi 104 seat and guide machine and VVR 120 valve grinder. None of those three come cheap and all of them will add horsepower simply by doing what they get paid for.
I've seen $500 heads and I can tell you none are without deficiencies. Whether that's a part that was re-used instad of replaced, or seat angles cut out of round, or gasket surfaces that are not flat, intakes that don't fit, or seat depths that vary... they all have problems and they all will have issues associated with them even on a low rpm driver.

i wonder what the difference is in a $50 hot tank of a block and a $150 hot tank?

Usually the tank and process itself. The cleaning process ussed where I go is a jet wash cabinet cycle, then and airless shot cabinet, then a jet wash again. that's because it cleans much etter than the EPA approved cleaners that have to be used (at least in CT) now. Again - a little knowledge is a big deal. Hot tanks don't get the crud from inside the water jackets very well anymore. If you're wondering why your .030 over truck engine runs hot it may be all the rust, scale, and casting slag that was left in it by the hot tank filled with Simple Green...lol.