Crankshaft

[Slug]

I need some advice on the crankshaft. 1973 340 started smoking and running crappy. So I decided to pull it apart and try to rebuild it. I got the trick flow heads, ordered the lunati roller cam and lifters. So now most of my money is gone. When I got to the crankshaft, the bearings and crank were shot. Scores that are pretty deep in both the main and rod journals. So I need a new crank. Can I just buy a mopar external balance crank and just put it in or do I need to get it balanced. I'm not going to be racing just some burnouts around town and some highway use. Did these motors come balancer from the factory?

 

[413]

Just turn the crank you have. Balancing is money well spent.

 

[DetMatt1]

How are the cylinder bores? Rings?

 

[Slug]

not bad, I ball bones them, the engine was 30 over already. Measured out ok.

 

[Slug]

Ball honed, this spell check is horrible

 

[Chryco Psycho]

Balancing is a must when replacing a crank or pistons .
Try to get your crank cut down as suggested above .

 

[Slug]

Thanks for the responces. Will do.

 

[moparleo]

If the crank is damaged you will have metal in the block. No turning back. Hot tank, cam bearings minimum if you are reusing the old pistons otherwise bore/hone. Check if align hone is needed, decks square and flat, and on...
Better save your pennies, this going to cost.$$
But you really knew that already....

 

[DetMatt1]

I have to agree with Leo, it’s expensive enough to do it halfway but then to have to redo it all the way after that…well I don’t need to tell you how that math looks.

 

[gs73rallye]

Just my two cents, but having your old crank reworked is probably half the price of buying a brand new crank. If it's a 1973 it's a cast crank. I would spend the money and upgrade to a forged. Your cast crank is externally balanced, so make sure you get the appropriate one, or you would have to change your balancer, and flywheel or torque converter. Don't rush it, save up your money and do it right.