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4G63 Flywheel Bolts. OEM or ARP?

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Im trying to decide if I should use new OEM flywheel bolts or ARPs on a 750hp 4G63 7 bolt build. I would go ARP, but I’ve read that they are slightly too long and bottom out in the crank. Does anyone have personal experience with the ARPs? Have you run the OEMs with success and if so, to what hp? What does everyone recommend?


You can make them shorter.Your machinist can do that in his lathe. Pretty common and easy job. I know many people running the OEM bolts over 500rwhp without a problem.

Yeah, my machinist said that he could trim them down. I'm just wondering if it's needed to use ARP or if new OEM bolts will be fine. Also, if ARP has a revised version that's the correct length, then that would be ideal.

Rather surprised they sell something that needs to be modified to use - is this a common thing or is it a problem with aftermarket flywheels with a thinner centre?

Don't know about that engine, but some have reported interference with some friction plate hubs interfering with the slightly higher heads of ARP flywheel bolts.

Always measure the length of aftermarket flywheel bolts guys.When I changed mine my friend and machinist told me so when I was rebuilding my block. Wouldn't have paid attention on that and it's called lack of experience.It's stupid easy to make such a mistake.If they go to far in they can block the crank from spinning in my case Mazda B6.

It might have to do with the 6 bolt crank vs. the 7 bolt crank. I'm not sure.

I had just read on an evo forum that someone had an issue. So I asked my machinist and he measured my Quartemaster 8 leg flywheel and 7 bolt crank, then compared it to the specs given by ARP online and confirmed that the ARP was slightly too long. I also know that the OEM bolts have a very shallow head and they were very close to the rivets on the disk, so I'm not sure if the ARPs have the same shallow head design or not.

I just called Buschur and they told me that 95% of their builds use OEM, so I think I'll just go that route.

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