How many stock cranks have you broke on the dyno Don?

2 or 3. but the failure rate is pretty hi because we probably only ran 6 - 8 motors with stock cranks

Is that on S/A and larger engines? Or have you broke them on the stock stuff too?

I am ordering the last of my parts to rebuild my engine (K301). The last thing I need to order is the steel crank from Midwest. It will be balanced.

as Smokey Yunick used to say "when ever you build a motor stick the longest rod possible in it"
that said, there's big gains when you first start using longer rods, once the rod ratio falls within a certain range the gains are not as noticeable. your info is incorrect. a longer rod gives you more dwell time at TDC . during this time more pressure is built above the piston which gives more torque. if you hang a degree when on it you can see the extra degrees of dwell at TDC.
personally I don't think you would know the difference between the 2 . building a motor like you are and lack of a dyno it will be difficult to get the most out of it.
if its a 4000 rpm motor no pop out

broke 2 in stock 14's

OK. Finally got the parts together to rebuild the engine.
LP head
ZK #3 cam, lifters, springs
Steel crank, balanced.
14 lb starter pulley
steel governor gear
Bosch coil and copper plug wire.
11 ball main bearings

Do I need a 36 lb fly wheel and if I do, will the flywheel fit under the fan shroud? Will I be able to swap engines without changing the length of the driveshaft? The pulling engine will only be used for pulling. What about cooling? If I need a flywheel, which one do you recommend?

How many RPM do you plan on turning it? As for a cooling fan you can use the small 12v boat fan MWSC sells, bolt a plastic fan from a Command style flywheel on it or just go without.

4,000 rpm. I would like to run a steel flywheel with a plastic fan but could not figure out which fan and steel flywheel combination would fit under the engine tin.

I would think with the heavy front pulley a 25# flywheel would be enough. As for getting it to fit under the stock tin I imagine that is going to be trial and error. I don't use any type of cooling at all so I am not much help. But plastic cuts pretty easy.