273 crankshaft, 5.2 Magnum

One thought I did have on this matter.. .while 30' up on a ladder in 28 degree temps this AM LOL..... I don't know of a reason for the Mopar engineers TO keep the same bobweight into the Magnum... but on the other hand, there might be production reasons to do so. (Like not changing tooling setups....)

BTW, I just corrected my ring weight numbers for the 273 2 BBL...my original number was a tad heavy. Now bobweight is 2163 grams (measured) vs 2161 gr for the 5.2....


Can't see why not..... if it is a crank that does the same job, has the same oiling, same dimensions, etc..... what is the detriment to doing so??? Would anyone really object to the news that we put a 273 cast crank in my son's 340? Balanced up easily (by design), has the strength to do the HP/torque we wanted.... My Mitsubishi Starion 2.6L turbo rally engine has VW flat top forged pistons in it... running 1.75 HP per CI.


It would be interesting to see what can be dug up on factory balance tolerances....
Ok I'm calling it. I have been searching for specs and can't find much at all. I have more important things to do than argue a point that I can't find the answer to. You win. If you or the op wants to put a 273 crank in a 318 Magnum knock yourself out. Post your results when you do. I would be curious as to what has to be done to make it work correctly. (balancer, flywheel, flex plate, converter, balance etc) I thought Magnum rods were lighter and pistons as well. The OP would be lucky if the original 273 bob weight was the same as the Magnum 318. Good luck.