Who knows??
Race Director
Joined: Oct 2000
Posts: 12,679
Likes: 3,130
From: Shamong, NJ
I don't have any of my GM parts books at the house (they're all in my shop), but I think that any 454 flexplate up to 1990 will work. If I remember correctly, all 454's with the two-piece rear main seal, use the same flexplate, where as the 91 and later 454's with the one piece seal, use a different flexplate.
Hopefully, someone else will chime in with a more definative answer.
Hopefully, someone else will chime in with a more definative answer.
Thread Starter
Racer
Joined: Mar 2009
Posts: 331
Likes: 1
From: Brooklin Ontario
I don't have any of my GM parts books at the house (they're all in my shop), but I think that any 454 flexplate up to 1990 will work. If I remember correctly, all 454's with the two-piece rear main seal, use the same flexplate, where as the 91 and later 454's with the one piece seal, use a different flexplate.
Hopefully, someone else will chime in with a more definative answer.
Hopefully, someone else will chime in with a more definative answer.
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
All 454 flex plate should be balanced the same, there should be no reason to have to mess with the weight that's welded onto it. As long as the shop knows it will be an externally balanced big block, they'll balance the rest of the rotating assembly accordingly.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
On the other hand, if during a rebuild of your engine, it was balanced by a shop by drilling another hole or adding weight to your flexplate, you would need to do the same balance modification to the new flexplate. Typically, external balance engines like the 400 and 454, are balanced with their harmonic damper and flywheel (or flexplate) in position on the crankshaft. If the shop balances the crank by adjusting the crank and leaving the harmonic damper and flywheel/flexplate alone, then part by part replacement is unaffected.
Thread Starter
Racer
Joined: Mar 2009
Posts: 331
Likes: 1
From: Brooklin Ontario
If it's a stock 454 flexplate and was not balanced specifically for your engine, then a stock replacement will be fine.
On the other hand, if during a rebuild of your engine, it was balanced by a shop by drilling another hole or adding weight to your flexplate, you would need to do the same balance modification to the new flexplate. Typically, external balance engines like the 400 and 454, are balanced with their harmonic damper and flywheel (or flexplate) in position on the crankshaft. If the shop balances the crank by adjusting the crank and leaving the harmonic damper and flywheel/flexplate alone, then part by part replacement is unaffected.
On the other hand, if during a rebuild of your engine, it was balanced by a shop by drilling another hole or adding weight to your flexplate, you would need to do the same balance modification to the new flexplate. Typically, external balance engines like the 400 and 454, are balanced with their harmonic damper and flywheel (or flexplate) in position on the crankshaft. If the shop balances the crank by adjusting the crank and leaving the harmonic damper and flywheel/flexplate alone, then part by part replacement is unaffected.
Thread Starter
Racer
Joined: Mar 2009
Posts: 331
Likes: 1
From: Brooklin Ontario
Later, Rog.
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