So my 272 had two sizes of head bolts and the ARP kit I purchased has three sizes. I have some used 8 grade head bolts from a 62. What do you think if I use the used head bolts on the ends and use the rest of the new ARP head bolts? ARP bolt kits for y-blocks are sold out in the usual places right now.

The early Y’s had only two sizes of cylinder head bolts.  The change to using the longer bolts at the upper row ends was a design change that occurred after the introduction of the Ford Y.  The ¼” additional length to the outside upper row head bolts happened in the mid Fifties likely due to some service issues with the shorter bolts either not torquing correctly or damage occurring to the threads in the block when using the shorter upper row bolts at the ends.

Assuming you have the longer bolts, I’ll suggest you try those in the end upper holes without the washers and if they screw completely in or bottom out at a point where the head bolt washer is still thicker than where the bottomed out bolt resides, then use the longer bolts at the ends.  The end bolt holes may need to be bottom tapped to get the additional threads to accommodate the longer bolts.  This happens on all year Y’s and not just the early ones.

Lorena, Texas (South of Waco)

Ted,

The heads just take the 4” bolts under the valve cover. They don’t have the longer bolts on the ends. So I can’t use the longer bolts in the new ARP head bolt kit for my 272.

I was thinking of using some used grade 8 head bolts I took off of a 62 292 . So I would be running two used grade 8 bolts and two new ARP bolts under the valve cover and of course the smaller bolts outside the valve cover will be new ARP bolts

Question: Would the used grade 8 bolts and new ARP bolts be compatible for the heads?

Did you try the longer bolts in the end ‘top row’ bolt holes?  If so, did they bottom out before the heads contacted the cylinder head and if so, how much ‘under head’ measurement was exposed.

As far as using the grade eight bolts from a later Y, then ‘Yes’, those particular bolts will have the same clamping force as the ARP bolts.

Lorena, Texas (South of Waco)

Ted,

I already took the head off. It had the 4 long bolts that were the same length. I might put the head back on and check the lengths which you recommended tomorrow.

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.

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.

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)

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?

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.