I have a 69 400 block with a 440 crank (according to the guy I bought it from - that makes it a 451. I bought the motor complete with the auto reverse manual and do not want ot use it. I bought a full complete 4 speed including bell linkage and zbar etc to put in my cuda - What I dont know is if the old setup was externally balanced. I have the old torque converter and the new flywheel, so should I be able to tell if they are balanced the same or maybe just take them to a engine shop and have them compare the balance? I dont want ot put it all together nad find out I need to pull everything out and get it balanced after burning out a main bearing due to shake.

anyone got a good way to solve this problem?

 

Welcome to the forum!
To put a 440 crank into a 400 block,the main journals have to be honed out to the larger 440 size of 2.75 inch.If he did that it is most likely internally balanced. Since this is a used motor, I would pull the oil pan and check the bearings. Did it have a stock damper?
Does the torque convertor have any weights on it? Stock flex plate?

john

 

You have a 69 400 block? The 400 block was not introduced until the early 70's. Are you sure you don't have a 383 block?

 

according to the casting number its a 400 block listed on the 440source website - could be a 70- I thought it was 69 1/2 - the build sheet I got from the guy shows 440 high performance crank but no specs on type steel or cast

 

1972 was the first year for the 400.

 

Tahoe, how about posting the casting number and serial number off the block,and posting a copy of the build sheet.

 

casting #4006530-400 is a 76-78 block accroding to 440source and as memory serves from a year ago that is the block I have. I'll get the build sheet to see if I can figure out the components. My big concern is putting it in my car and finding out its unbalanced

 

Great! waiting to see what it has for rods and pistons. Again,any info on the damper and flex plate and torque convertor will help. But I am almost 100% sure it will be internally balanced.

john

 

Was just checking out your pics,I am so jealous, a big garage and a viper!

 

I'll chime in here for a second...don't ever guess....they turned down the 440 crank mains to the the size of the 400 mains...that is common practice...a forged steel crank will have a thick line where the metal was pressed when it was forged...a cast crank will have a very thin line where the sand casts met...the common practice is forged equals internal balance and cast equals external balance...if you do not know...pull the rotating assy....crank, rod and pistons and have your rotating assy internally balanced...this costs 250-350 bucks depending on the machine shop...it takes all of the guess work out of what someone else has done..

Eric

 

Eric, thanks for chiming in. I just can't imagine anyone putting a 440 crank into a b block would not get it internally balanced! But,you are right. If in doubt get it checked cause you just never know!

john

 

Exterally balanced engines have a counerweighted damper and torque converter.