Flywheel bolts

M

MikeHunt

Member
Can you use any good grade 8 bolts for the flywheel bolts on a straight 8, or do they have to be special? Can't find any specific to the 8.
Thank you!
 
If it was me, I would see what the thread size and under head length was, and then look in an ARP catalog and match something up.

ARP.JPG
 
The factory bolts have a longer shoulder that measures .373 so it fits tight into the crank flange hole...it's a specific design, just can't find anything out there like it. Including ARP. So if it was YOU, then what would you do? ;-)
 
MikeHunt said:
The factory bolts have a longer shoulder that measures .373 so it fits tight into the crank flange hole...it's a specific design, just can't find anything out there like it. Including ARP. So if it was YOU, then what would you do? ;-)
Click to expand...
Well, you were asking if you could use any grade 8 bolt, so I thought you had found a grade 8 bolt you could use. Now you mention the shoulder on the stock bolt? I would reuse the stock bolts if I could:)
 
ARP only has 12 pt bolts...shoulder diameter is not right. Mcmaster Carr has AN bolts that might work, will post once I know for sure.
 
***UPDATE***

Mcmaster Carr has a great replacement bolt that works perfect....part# 94622A432 in packs of 5...of course.

buick 8 bolt.jpg


buick 8 flange.jpg
 
You can get longer bolts with the shoulder and trim to size. Also, any machinist can make you bolts or trim them to size as needed better than free hand on a grinder. There is going to be other vehicles with same bolt. Recall GM put same parts on multiple cars for profitability.

Here is one of my go to places.

Automotive Bulk Fasteners — AMK Products, Inc.
 
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