For my build im trying to find a flex plate to mate a bbc and built 700r4. The bb has a 1 piece main seal, and the engine is internal balanced. The torque converter is 10.75" bolt spacing. Summit cant help .
CK5
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Flex plate
- Thread starter 53chevy
- Start date
So, you have a Gen V or Gen VI 454 with an internal balance crank? Well, you got yourself in a pickle. You have a couple options. You can use the GM 12561217 flexplate for the 427 crate engine. This is a single piece seal engine but only comes in the 11.5 inch spacing. You would have to slot 3 holes for a 700R4. You may look and see if you can find a dual pattern flexplate for an 8.1L. They are internal and use a single piece seal. The other options are to have someone with balancing abilities take the weight off a 454 plate and rebalance to neutral or use a old school 2 piece seal 350 plate. I know the center hole is bigger but I know people get away with it.
I totally missed it's internally balanced, just slot the holes for the torque converter. Been done many times with at die grinder, if you want something more precise then take it to a machine shop and have them set it up in their mill and drill it that way. I know of no other options.
Exactly. That is one I mentioned in my previous post. The old school small block and 396, 402 and 427 internal balance plates are the same part. The center hole wont fit the crank correctly on a one piece seal big block crank but people use them with no issues.
