383 sbc

Old 02-17-2008, 10:28 AM
Junior Member
Thread Starter
Join Date: Dec 2005
Posts: 2
Default 383 sbc

Have a 383 with balanced eagle assembly...it has a auto flexplate on it balanced and sfi...the front balancer is a stock 400 sbc balanced to flywheel I'm assuming...I want to replace this balancer and use a sfi balancer..question?? does it have to be rebalanced to flex plate?? I have a fairly new 350 sfi fluid balancer..was told it might work but not sure enough??

help needed

chevyracer1960 is offline  
Old 02-17-2008, 01:35 PM
Senior Member
Join Date: Sep 2007
Posts: 4,143

balancer must be one for an external balanced 400 if that is what the crankshaft is.
Tod74 is offline  
Old 02-17-2008, 08:12 PM
Senior Member
Join Date: Feb 2004
Location: Leonard, Texas
Posts: 414

Originally Posted by Tod74
balancer must be one for an external balanced 400 if that is what the crankshaft is.
I 2nd that!
SST4530 is offline  
Old 02-17-2008, 11:37 PM
Senior Member
Join Date: Feb 2006
Location: VA Hospital, Dallas, Tx (214 302 1924) cell-972-464-7400
Posts: 540

Somehow you need to find out if your Eagle Assembly is Internal or External balanced. It is sold both ways.

The type of balancing also can be changed by the balancing shop that balanced it. If you are running the engine and it has no vibrations then that says that whatever you have is right. If you have a factory 400 balancer the balancer is for an external balanced engine, so you will need the new one to also be for an external balanced engine. The factory 400 balancer had what looks like a notch cut from the outside of it on one side.

iF that is what you have and it has already worked good, the change will be simple, Buy an external balanced balancer and install it. Careful though. Most aftermarket balancers need to be fitted to the crankshaft by internal honing of the balancer. The flexplate should also have a small weight welded to one side of it, if it is external balanced.

If this engine has never run, don't guess at it. Check with Eagle about what it is, if you bought it from Eagle. If you didn't call Eagl;e and ask them how you can tell if the assembly is from them and what to look for if it is internal or externally balanced.

A machine shop that balances can also tell you by weighing the parts and spinning the crank for balancing. Many shops can tell you by just looking at the crank.

edvancedengines is offline  
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service