By "fit" if you mean can be wedged into the engine compartment, then a lot. If by fit, you mean bolt-in, then the question gets a little muddier. The 4.0L block was used in Wranglers and Cherokees for YEARS, and it can be adapted to fit most Wrangler or Cherokee models with the level of difficulty varying by model year and how well the options match from the donor vehicle to the surrogate.
Have you changed your oil lately? You can try adding 10/40 wt. oil the next time you change oil.
I've never worked with a blockhead motor, but I'd think so, because as far as I know the only thing that's changed with Harley engines in the last 30-40 years is the top end.
The 40 amp motor probably produces double the horsepower of the 22 amp motor.
you might try spraying WD-40 into the bearings of the fan and fan motor, and then spinning the motor by hand a few times. If this does work, you will have to add a regular lubricating oil to the places where you have sprayed the WD-40, as it will dry out fairly quickly. I would recommend using Gunk 'Super Oil'.
Yes this is what we call efficiency of the motor. We give 100 but the motor in turn gives 40, so its efficiency is 40%
No
40
WD-40
40 Psi
If you are not looking for room around them, 64 will fit.
It's difficult to answer. As far as I know, every American gun manufacturer makes numerous models in .40 and almost every other manufacturer does also.
10w/40