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That combo may likely last longer in a dragster than a heavy street car. Just like an 8 3/4..takes alot more grunting to move a 2 ton than a 1 ton.



How do you figure this?
Were not talking 8 3/4 rears LOL
The engine doesnt know what its in, or cares for that matter.



Its just common sense. If the crank is working harder to turn the shaft there will be more flexing... and thats what tears those blocks up.

In this scenario, both cars would have the same gearing and trans. The lighter car runs faster because the motor is doing less "work" to move it. The motor is subject to the laws of physics just like you or I. Thats all I'm saying.



Sorry My common sense must be broken
How does it work harder, and make more stress?
If the engine makes 800 hp, and you shift it a 7K in car A weighs 3800 lbs.
Car be weighs 2000 lbs. The engine still makes 800hp, and the torque and power range doesnt change, so you shift it again at 7K
Explain to me in lamens terms how it works harder to achieve the same power level?
Were not looking at E/T time slips here, acceleration, 60 ft times...No increments.
How does the engine live longer in the lighter car?
If this were true they would never blow up on the dyno. The engine see's the load and tries to move it.

I have had some in depth college Physics classes, i dont see how weight of a vehicle or chassis setup can effect engine longevity.

Just a friendly debate here..

IMO vehicle size has nothing to due with the stability of a engine. Things like bearing clearance, and bore thickness, detonation does however.

Just think about what your trying to say.

If told you the weight of a vehicle in theory has little to do with max top end speed given a perfectly flat surface you would also think I am



No problem, my point was pretty much what Bob suggested..the crank being an extention of the drive shaft. etc. And like he said most of the stress on the block would occur in getting the heavy car moving. The way i see it, the crank is always trying to exit the block from the forces of combustion. The only thing keeping it there are the main caps. If the crank encounters a bigger load, some of that torsional force will "deflect" putting stress on the mains and the block surrounding the mains. As an illustration, suppose you had a hand crank like on a Model T and as you were applying muscle you encounterd more compression than usual,the hand crank will deflect for a moment. Since the bottom end on a motor is basicly rigid even the smallest bit of deflection will be "felt" by the block, enabling a crack at the weakest point. I understand you and others do not believe any added torsional deflection is occuring in a heavy vs light car. Thats the part that just seems to make sense to me, i.e., there is more resistance in the heavier car..like in Newtons second law..that which is at rest tends to stay at rest..so more force is needed to get it in motion. And in my view, some of that force..even if very small, ends up being felt by the block.