ARP Head Studs 425 VS 625

[Tiggerog]

Hello.

So I have been doing a lot of research on this for 3 weeks now and I am going to be putting a new turbo on my truck.

Either a s464 2nd Gen swap or a Holset Cheetah and I’m not upgrading the fuel system other then a lift pump since I have a new one sitting around.

The question is will 425’s be fine with the proper retorque sequence for 45 psi or will I need to go to 625’s.

Thanks for any help!

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[MrAnthrope]

Does this help at all?

https://www.igotacummins.com/threads...ARP-425-vs-625

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[TexNeck]

Hello.

So I have been doing a lot of research on this for 3 weeks now and I am going to be putting a new turbo on my truck.

Either a s464 2nd Gen swap or a Holset Cheetah and I’m not upgrading the fuel system other then a lift pump since I have a new one sitting around.

The question is will 425’s be fine with the proper retorque sequence for 45 psi or will I need to go to 625’s.

Thanks for any help!

You’ll be fine with the 425 studs running less than 50psi

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[Chrisn162001]

If the extra money's not a big deal go 625s.

My reason behind it is 425s should be hot retorqued 625s don’t need retorque.

It kinda a pain to tear down to retorque.


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[cumminsdieselfreak]

You’ll be fine with the 425 studs running less than 50psi

If the extra money's not a big deal go 625s.

My reason behind it is 425s should be hot retorqued 625s don’t need to retorque.

It kinda a pain to tear down to retorque.

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Both of these are correct.

Having to retorque the 425s is a pain in the butt.

If you're paying someone to do it then it'd be better to go 625s but if you're doing it yourself and don't mind the retorque then the 425s are a great choice for your setup as

Mike stated.

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[RamIt]

625s.

Do it once, do it right.

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