I wanted to make a point that might seem trival to some but is very important to me. Clearances are the key factory not tolerances. I belive that people tend to interchange the too when they are quite different. Tolerance is how close to a given desing spec. a given part or assembly is manufactured to. Clearance is the amount of space between two parts or assembly's. I would challenge most people to show me were bearing clearances in general have been reduced on crank journals, ring to bore etc... While tolerances are being controlled much more closely especily in reguards to concentricity and we are seeing less tolerance stacking very few engines even new designs have seen any significant reduction in clearnces. The few that have are either ultra luxury or ultra performance. I have compared alot of engines spec.'s from various manufactures and find strikeing similaritys withing a company even on different engine platforms. You can only reduce the clearances so much before you can no longer reliable manufacture it affordably. You will also get to the point of deminishing returns in alot of areas like cost, durability, efficency(too much friction). I will try to get you the spec.'s for Dodge 3.9V6, 5.2V8, 5.9V8 and their somewhat new 4.7OHCV8. I have them at home so it is just a matter of digging out the unit repair manuals.