Posted By: 66er
3.91 stroke BB crank - 11/24/12 06:33 PM
Which crank would be stronger \ last longer. A offset ground factory steel crank with the mains ground to 400 size, or a chinese 4340 forged crank 
3.91 stroke BB crank
Posted By: Thumperdart
Re: 3.91 stroke BB crank - 11/24/12 06:43 PM
Quote:My 413 cut crank is going on over 13 years................
Which crank would be stronger \ last longer. A offset ground factory steel crank with the mains ground to 400 size, or a chinese 4340 forged crank
Posted By: Cab_Burge
Re: 3.91 stroke BB crank - 11/24/12 06:51 PM
Quote:Probally 4340, I can't remember the type and number of the stock forged steel cranks Mopar put in the original HP and non HP motors. I have had several stock forged steel crank offset ground and then heat treated, they last
Which crank would be stronger \ last longer. A offset ground factory steel crank with the mains ground to 400 size, or a chinese 4340 forged crank
I have also had a Chinese RB 4.150 stroke 4340 crank offset ground to 4.300 stroke with BB chevy rod journals and cut the counter weigts and mains down to fit in my 400 block, I had it reheattreated afterwards also 5 yrs whupping on it so far 
Both ways will work 
Posted By: 66er
Re: 3.91 stroke BB crank - 11/24/12 06:53 PM
Quote:Quote:My 413 cut crank is going on over 13 years................
Which crank would be stronger \ last longer. A offset ground factory steel crank with the mains ground to 400 size, or a chinese 4340 forged crank
Ya, I read your post yesterday. It caused me to think about having a back-up crank ground. I can get a good core cheap. How many RPMs do you turn yours?
Posted By: Thumperdart
Re: 3.91 stroke BB crank - 11/24/12 07:10 PM
Seems it likes 6800-7200 shift points and traps around 7200 but I`ve been as high as 7800 accidently but seems fine..........the crank was actually bent when Pettis found it so Jason flipped it around to the high spot, smacked it a few times with a chissel and sledge hammer 
and it`s still goin strong......... 
and it`s still goin strong.........
Posted By: 66er
Re: 3.91 stroke BB crank - 11/24/12 07:23 PM
Quote:
Seems it likes 6800-7200 shift points and traps around 7200 but I`ve been as high as 7800 accidently but seems fine..........the crank was actually bent when Pettis found it so Jason flipped it around to the high spot, smacked it a few times with a chissel and sledge hammer
Looks like you beat on yours harder that's me. I shift at 6500-6700 and out the end 6700. that a bad engine!
Posted By: Thumperdart
Re: 3.91 stroke BB crank - 11/24/12 07:31 PM
Could be because of the 275-280 dur @.050 that kills a bit of bottom end but charges nicely mid track on up.