cast or forged crank?

[70 340]

Was wondering which crank to use for 71 340 build.
I have a cast that came with motor. The last guy had a vibration damper for a forged crank on it.I also have a forged 273 crank.Would it be any better to use it?Is there any problems besides the right damper and tork converter?
Thanks for your advise.

[dodge freak 2]

Cast will flex a little at high rpms--just what 340 engines are to be good for with their short stroke.

The 273 steel crank is about 3 pounds lighter than the 340 steel crank but is strong enough--way better than the cast crank which is harder $$ to balance.

I see no good reason to rebuilt a 340 using a cast crank...besides the re-sale valve be much higher with a steel crank-even from a 273 motor.

[mopar12372]

cast cranks are good up to 7000 rpm , steel cranks are insurance . go with steel on a performance build cast for a stocker .

[dodge freak 2]

Isn't inter balancing a cast crank 340 big $$? He is saying he has no dampener of flex plate for the 340 cast crank. Think it be cheaper just to find a 340 steel crank once you get it balanced...new dampeners are easy to get...not so for a 340 external balanced crank.   

[Chryco Psycho]

either way you will have to balance the rotating assy , I would use a light piston & the steel crank though

[dodge freak 2]

 What about these..if the motor is good at .030 over


SRP Chrysler Flat Top Pistons:

http://www.jegs.com/i/SRP/867/142068/10002/-1?parentProductId=753722

[dodge freak 2]

either way you will have to balance the rotating assy , I would use a light piston & the steel crank though

Yes but I thought to internally balance a cast crank 340 the crank needs more metal  added to it then a forged crank...and the metal isn't cheap. 

[mopar12372]

eather way you have to balance the engine , it costs eather way.

[Tonefiend]

I got a forged crank #2532457  for my build.  Is that an internally balanced crank?

[dodge freak 2]

I think all factory forged cranks are internal balanced...just the some cast cranks are ex.

[Chryco Psycho]

in a 340 all steel cranks are internally balanced

[Chryco Psycho]

What about these..if the motor is good at .030 over


SRP Chrysler Flat Top Pistons:

http://www.jegs.com/i/SRP/867/142068/10002/-1?parentProductId=753722

 SRP makes a great piston 
 using a lighter piston with either crank will require less metal added to the crank to get it to balance & allow the engine to rev quicker

[moper]

forged 340 cranks are not that hard to find... You may need to add metal to the 273 crank to get it to balance.

[Dusty1]

Do '68 340's have steel cranks?

[Chryco Psycho]

yes , only the 73 had the cast crank 340