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Stock Head Bolts vs. Head Studs


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Hey all!

I hope everyone's driving season has been great. I have a few questions.

1) Is anyone running increased boost on stock head bolts? If so, how much boost

are you running?

2) What is the maximum boost the stock head bolts can handle?

I'm doing some preliminary work on some modifications. I am planning on doing

motor work and trying to decide if I should go with studs or stock head bolts.

My concern is accessibility. I only plan on removing the engine for my piston

upgrade. after that it will be cylinder head work, but I want to do it in-car.

know that if I install studs, I will need to almost remove the engine to get the

cylinder heads off whereas with stock bolts, they can come off with the head.

However tensile strength of the stock bolts are in question as I an planning on

running high boost (of course, determined by the temps of the exhaust manifold).

Any insight will be helpful.



'14 Nike Shox

'12 Range Rover Sport

'01 Esprit V8

'95 Ducati 916

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I know of a few folks who are running increased boost with the standard hard bolts - but still less that 1 bar.

If you are planning to run boost greater than 1 bar, then I would recommend the higher strength head studs. Naturally, you have a whole load of other considerations then, but that is the way I would go / have gone in the past.


Mike S

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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