Playing around with some internal weights and comparisons.

FYI, my Molnar 4340 4.25 stroke crank with 2.20 rod journals weighs exactly 70 lbs. after being drilled for balancing.

Molnar 7.1" rod, pin and Mahle piston weighs 1490 grams

Mopar stock 6.76 rod, pin and cast piston from '73 440 forged crank motor weighs 1875 grams

I've played with the idea of doing a 470" B with cast crank...you could really get bobweights down and have neutral balance with the right pistons and rods.

I've read of SS racers using cast cranks, but for how long before it fails? I can't seem to get a straight answer whenever it's brought up...

Cast crank is lighter, but not sure how much , but it's enough that it required external weighting to balance.

A friend of mine once told me that Chrysler made their forged cranks with a "Rotary Axe" and for that reason they were very tough for the time and of course that is what they look like, too.

A cast crank is lighter and has fewer stress risers to begin with. They have their place in our world, but if I was wanting to really spin up a motor I would want a forged crank. If my rev limit was 6,000 rpm I would be comfortable with cast.

The crank for my low deck 470 weighs 54.5 lbs on my shipping scale. It is the lightest big block crank that I've ever seen. I have a handful of 65 to 75 lb cranks sitting around the shop so it is nice to lift one that is less than 55 lbs.

What type is it?

It is a SCAT Superlight crank. Very nice machine work, gun drilled, undercut counterweights, aero cuts, all the tricks.

The factory 383 forged crank that I have on hand weighs 67 lbs so this crank is 13 lbs lighter. The pistons and rods are probably 8 lbs lighter than OEM.

not very scientific but i weighed a cast and forged 440 crank on a bathroom scale and there was virtually no difference. i had always been told a cast crank was about 10lbs lighter but the cranks i have had no difference that i could see.

I've weighed cast and forged 440 cranks and don't see much difference in weight. I think the cast crank has a lower bobweight, but the scale weight is roughly the same.

I weighed two years ago and remember there being about a 8-10 pound difference. Maybe my memory is foggy? Not sure.

I just weighed a 440 cast and 440 forged crank. They were both 71 lbs. The cast crank might have been 1/2 pound lighter but I can't tell for sure. The scale reads in 1/2 lb increments so I'm going to say it is too close to call.

Awesome!

Thanks.

Sold two 400 cast cranks to a fellow member, he wrote back to say the cast crank was 4.5 pounds lighter than the steel one. Was going to use it in a 383 stock class car. I still have a cast crank out of a 77 police engine, I'll weight it tomorrow along with a steel one.