Just want to confirm the correct spec for 400/430/455 flywheel to crankshaft bolts: 7/16. - 20 3/4 long? Torque 60 ft lbs? What’s a good source?
JW recommended the ARP bolts. Had to dig up the part number in an E-mail from Jim. ARP-200-2902. https://arp-bolts.com/kits/arpkit-detail.php?RecordID=771 https://www.amazon.com/ARP-200-2902-Flex-Plate-Bolt/dp/B003TTXN9O
This is one area of the motor where the factory bolts suffice just fine. I have reused them 6 or more times. put your green somewhere else unless you do not have any factory ones.
On the Buicks....the both strength isn't the issue from my experience it's the small area under the 5/8 head that from what I've seen with the probably dozen of cracked 455 flexplates has to be the cause.....arp has a 3/4 head with MUCH more surface area grabbing the plate ...now granted I've got a good 25 flexplates with no cracks but have tosses plenty that were originating from under the bolt head...just my observations
With an aftermarket sfi thicker plate....you would probably not see a cracking situation.....but forvthe cost of both the plates and bolts...good insurance imo
The ARP bolts are nice 12 point….75 foot lbs torque, use blue loctite. As Hugger stated, way more surface area under the head. A drop in the bucket versus the cost of building these motors.
