Good idea thanks

Get a thread restoring tap and die set for cleaning out existing threads.

1 example of many:
https://www.amazon.com/Lang-Tools-2581-26-Piece-Restorer/dp/B00DTEFSWY/ref=asc_df_B00DTEFSWY/?tag=hyprod-20&linkCode=df0&hvadid=309807921328&hvpos=&hvnetw=g&hvrand=16359464428981792935&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9010796&hvtargid=pla-492697560931&psc=1

You can make them by cutting 3 or four grooves along the length of a grade 8 bolt.


Lawrenceville, GA

So I decided to do a trial fit of the ARP bolts without nuts. I put some oil on the threads and the longer end bolts went in fine with no space sticking up so I can use them. I am changing head gaskets and the previous engine builder put some thread dressing on the bolts which gave me a false depth reading on the end bolts.

Thanks for all the advice.

On any bolt with washer, or stud with washer, the chamfer goes to the head or nut side, and the flat goes against the part being clamped.  If two washers are needed in a high torque situation such as head bolts, they should be grade 8 and the flats go to the part being clamped.  The rounded side goes to the bolt head or nut side.  All washers, unless cam ground, have a flat side and a rounded side because they were stamped out before being hardened.  Joe-JDC

JDC

I think this question can be answered in different ways. I use studs when ever I can so I’m more familiar with those, however like Ted, I check the threads in the holes with either one. I have a thread cleaner kit (these are not taps) and it’s what I check for the depths of the threads also. I’m more concerned with the proper amount of threads in the hole to make for a more secure attachment. When I know the treads are good and there is a sufficient number of them I like to use a hardened washer for a better distribution of torque to a larger diameter surface mating with the cylinder head and under side of the bolt head. I also use those dental hooks to reach down in the block to count threads. I assume nothing. I also had to grind flat the impact socket I used for torquing the bolt heads on the car. 
With our stock engines this probably a little over kill but I’m pretty annal with stock engines because I’ve so many racing ones and check all the same things on each. I’m not an engine builder so none of my customers can come back. I’m the only one. A good stock engine may have its heads off 2 maybe 3 times in its life but my racing engine 10 to 20 or more so that’s why I really like studs. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

The ARP bolt kit comes with washers that are chamfered. Would I add a hardened flat washer in between the head surface and the ARP washer?

My own rule of thumb is as long as the cylinder head bolt goes into the hole with anything less than the thickness of the head bolt washer being exposed under the head bolt when it’s bottomed out, then life is good when using the thicker head bolt washers.  I check all Y-Block assemblies for head bolt depth as there is some variability in those depths as supplied by the factory.

As James mentions, using a second hardened head bolt washer is a viable option for when the head bolts are too long for a given hole.  While the head bolt holes in the blocks may be deep enough, the existing threads may not go to the bottom of those holes.  In those events, a bottoming tap can be used to add another two/three threads to the holes.  When excessively milling the heads and/or decks, the bolt holes do get shallower at which point using double head bolt washers or bottom tapping the holes is required anyhow.  When doing the cylinder head test a few years back with over two dozen different cylinder heads, double head bolt washers were required with some of the heads.  The 312 dyno mule currently uses double head bolt washers as a result of the decks and heads being both heavily milled.  It's much easier to use the double head bolt washers rather than contend with shortening up the head bolts.

Lorena, Texas (South of Waco)

I put the head on tonight to check bolt length with the longest of the ARP bolts on the ends of the head. Without the washer on, there was 1/16 inch gap between the bolt head and the head surface. The given washers for the bolts are 1/8” thick So I think I will be putting my shorter used 8 grade bolts on the ends of the heads to prevent bottoming out. Thanks for the help.

I’ve 2 ARP hardened washers many times under their head bolts and with their studs with nuts when necessary. I just added ARP’s to my 56 when I took the heads off. There was a few incorrect stock ones. Seemed like the right thing to do. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.