[olddog]

Well Ford was putting 429 engines in dump trucks with heads and cam that gave them stump pulling torque at low rpm. Totally out of breath long before 4000 rpm.

At about the same time, they were dropping 428 engines into Mustangs as high performance machines.

428 FE ------ bore 4.130 x stroke of 3.98
429 385 series bore 4.360 x stroke of 3.590

That always bugged me back in my puppy days. Why was the short stroke engine that is supposed to be ideal for high rpm, in the dump truck, and the long stroke engine that is supposed to be ideal for low end torque, in the Mustang?

Well the answer is because Power output of a given cubic inch displacement, at a given volumetric efficiency (same amount of fuel and air), is the same regardless what bore and stroke combination got you to that CID. In the old days, with crappy head designs, the big bore allowed bigger valves, making it easier to pump more air. Today with good flowing heads and the fact that smaller bores make meeting emission standards easier, engines tend to be long stroke and small bores.

The power output is irrelevant. Power is just a question of how much air can you pump.

As for spinning a rotating assemble fast. If you can get a rod bolt strong enough to not stretch, when the forces required to stop the pistons at the top of the bore and reverse its direction occurs, then you do not have to worry about spinning a bearing. As long as the rod and wrist pin can take those same forces, then your good to go. Well assuming the crankshaft doesn't flex too much and crack, and you were smart enough to balance it. These are just physics calculations that any good engineer can do. Huge engines can be designed to spin very fast, but the materials required gets expensive.