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Flywheel for 401 in 69 AMX with BW 4 speed

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SC397 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2021 at 7:48am
Originally posted by Trader Trader wrote:

It looks like your engine was internally balanced, just remove the weight and it would have been very close. Expensive to do, but nice to have.
By the look of it, if you want a billet neutral balance flywheel for racing in the future, it would likely not be a problem.

No.  They had to do the same thing to mine to externally balance it.  Not expensive to do either.  
IMG_2657 by Rick Jones, on Flickr
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jerryw42 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2021 at 8:41am
As an update, I purchased the Jeg's flywheel. It seems to fit the crankshaft. I have had issues finding the correct bolts to attach the flywheel. The Pontiac bolts that someone suggested do not work. They are apparently 7/16 20 by close to one inch. The 401 crankshaft requires 1/2 20 bolts as does a 69 390 I have as well as a 70's 360. I have generic grade 8 1/2 inch  20 thread one inch bolts that fit but extend past the flange about 1/8 inch which looks as if it could interfere with the rear seal. The bolt heads are identical to the bolts I have that came out of the 360 (which had the adapter for the GM automatic). I have seen a thread that indicated the head with that thickness will interfere with the clutch action so I am concerned with that. I can get the bolts in 3/4 inch however my concern is that there may not be enough thread area in the crankshaft. I have suspended the search for the correct bolt until the engine balance is complete which is on hold until a new harmonic dampener arrives hopefully today. I am moving forward with the balancing as I have not only replaced the flywheel but the only pistons I could get for sixty over were Keith Black ones and not the same weight as the originals. So far, nothing is easy or cheap about this install which is just to replace a ruined street engine and not to build a higher performance or race engine. As soon as I have a final configuration I will post in detail what worked.    
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2021 at 9:51am
Just surprised at the amount of weight removed from the same area of the factory counter weight!
As for flywheel bolts, use Jeep 4.0l, they are 1/2"-20x7/8", example:
Thread sticks out of the flange by about 0.040". Plenty of room to get the spacer plate in and out.
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