RB VS B Blocks

T67POWER said

I guess there is a difference in the crank though.


Big Block Mopar Crankshaft Part #'s
Part# Engine Material Comments
2268114 383 4BBL Forged
3462922 383 / 400 2BBL Cast Externally Balanced
3672000 400 4BBL Cast Premium Cast Crank<<<<<<<:evil3:
Suitable for mild hop-ups
2536983 67-71 440 4BBL Forged A good general crankshaft
3512036 70-72 440 6BBL Forged Externally balanced
premium crank
3671283 72-73 440 4BBL Forged A good general crankshaft
3671242 73 440 4BBL Forged Balanced for different
weight pistons
3751889 74 440 2&4 BBL Cast Externally balanced
3751899 74 440 HiPo Forged A good general crankshaft
2406240 413/426 Max Wedge Forged Best RB crankshaft

Click to expand...

No not really, "factory" 400's used cast cranks and back in those days it was either cast or forged (there wasn't different grades you could choose from) I'm not aware of being able to order your 440 or later on your 400 with a extra special crank. Back in those days if you were building 400HP or lower use cast (remember these are old world cast cranks) everything over 400 use forged. With few exceptions forged cranks are internally balanced and cast externally balanced. The 440 6 pak crank required an external balancer because of the heavier con rods, more or less. Nowadays you can buy basic quality forged cranks and top of line forged cranks but I believe it's not necessarily the steel involved but more the process, quality control and testing at the molecular level which seperates a good quality crank from a top quality crank. That and price of course.

Now they do list a forged crank for the 400 in 71-72 cars but guess what, it's actually the 383 forged crank or what was left over when the 383 was discontinued in 71-72.