Ford balance to a MASS production setting, not to the much finer degree done by engine shops, due to labour/time involved.
If they balance the engine to a finer degree it will be better end of, especially at higher rpm putting less load on the engine components, for those that don't agree about balancing why not just go and take OFF your wheel balance weights and drive like that all the time, or do you think it makes a difference ?
I get all my engines balanced, even having the rods done end to end, so matched little ends and matched big ends, the difference is VERY noticeable.
The flywheels are very heavy on 2wd cossie at 8.9KG, 4wd are 9.2-9.7KG(they vary), so lightening has a disproportionately good effect, a basic lighten will see the 2wd down to 6.6KG by skimming out a mass of material at the rear surrounding the ring gear.
Lightening rods and pistons is also ace when you consider the forces at 7000rpm, they are going up and down 116 times a SECOND, that's to the top, dead stop, full reverse, dead stop full reverse direction again, any weight that can be taken off helps longevity.
I have had every engine I've built balanced, some lightened, always been very noticeable smoothness wise.
Balancing the flywheel is good, esp where done seperate, they are balanced to be neutral, that's why they have marks on them but can always be improved upon.
tabetha