Bolts versus Studs
 

At what point do bolts versus studs become necessary? I have taken some recently acquired aluminum heads to the shop to be resurfaced, and because of some imperfections may require a deck surface removal of 0.020 to cleanup, which got me to thinking whether aluminum or iron, at what point of deck surface removal do bolts become obsolete and studs become necessary for proper clamping forced?

The choice of going over to studs has nothing to do with the deck surface condition, it's all about maintaining clamping force on the head gasket with very high hp cylinder pressures and secondarily to ease distortion of the cylinder Bore.

You will be fine with bolts that are in good condition even if your making up to 600 hp.

Steve, sorry I didn't make my point clear. But what I was referring to is how much deck surface removal of either the heads or the block that bolts are no longer adequate. For example if you remove. 020 of head surface and. 01 of block surface, you now have. 030 of surface removal. Are the bolts now too long?
The OEM bolts and aftermarket fasteners may not take this into consideration and therefore you may be using a bolt that is too long, negating any recommended torque value and clamping force.

In days gone by builders of motors to be run the in NHRA stock and super stock classes seaking the highest compression they could within the rules would mill / deck the tops of the blocks that had factory valve notches .100" or more to remove the notches and still since there where no studs available at the time run bolts with no issue whatsoever!

This would often be done in conjunction with milling the heads .060".

Cuts like your talking about required no change over to studs weather you talking about cutting a iron or Aluminum head.

As a side note looking back , I do not think that decking these race blocks to gain like a 1/4 point of compression was worth the loss of air flow between.200" to .300"!

Hardened washers.

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