400sbc flex plate

[potionmaker]

I just pulled out the old 305sb from my '86 blazer and ready to install the 400sb. I thought I need to change the flex plate but they are both 168-tooth plates and same size. Is the difference in the balancing (305 = internal and 400 = external)? How can you tell the flex plates apart? Thanks everyone for the help!!
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[potionmaker]

Here's an in-process shot (first time posting a pic, let me know if you can see it)

 

[potionmaker]

mmkay...that didnt work. Hmmmmmmmm. Gonna have to investigate

 

[ou8mud2]

flexplate issues

you are right that a 400 is externally balanced. you should be able to see small counterweights welded to the flexplate off of the 400. that should be the difference between the two.
SS

 

[Beast388]

you are right that a 400 is externally balanced. you should be able to see small counterweights welded to the flexplate off of the 400. that should be the difference between the two.
SS

2nd that!

 

[Chaddy]

3d that. The weights must be in the same spot.

 

[potionmaker]

aaaahhhhh....i got it now. Thanks for clearing that up for me. I know this is gonna sound stupid, but any pointers for posting pics would be great. I tried the attachment button (paper clip thingy) several times but had no luck.

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