Can you help me ID this head?

N0rt0nelectr@

N0rt0nelectr@

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I have a head that I think is off of a model 88 or 99. The casting number is 22707 R, using the info on the INOA web site posted by Atlantic Green 22707 is either a 88 or 99 but what I'm interested in is what the R means if anything. There is another casting number on the bottom 23166. Here are pictures of what I have.

John in Texas Can you help me ID this head? Can you help me ID this head?
 

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Squish band on the rear/intake side looks bigger than front. Therefore looks to be a Desaxe engine 750 head to me.
6-7/8" or 7-1/8" center to center of widest bolt pattern?
R is just the individual mold used for the top part of the head casting.
Intake valves 1.5" on 750 and 1.4" on 500/600/650
 
It appears Atlantic Green website page when you Google states;
“It has the casting mold number 22707 ocasionally with a suffix of K or L on top core of the head. By 1963 the mold number has been eliminated completely. It additionally has the casting mold number of 23166 on the bottom core of the head. The 23166 mold fixture is used later on in the early atlas, but the 650SS head still uses the small head bolt pattern spacing. The 72mm barrel spigot relief ...”

No mention of the letter R
 
dynodave said:
Squish band on the rear/intake side looks bigger than front. Therefore looks to be a Desaxe engine 750 head to me.
6-7/8" or 7-1/8" center to center of widest bolt pattern?
R is just the individual mold used for the top part of the head casting.
Intake valves 1.5" on 750 and 1.4" on 500/600/650
Click to expand...

Years ago I ordered a valve, guide & spring set from RGM for a late 500 and that is what is in the head. I had originally thought to use the head on my 58 88 but thought better of it knowing that I would have to change pipes, carburetors and lord know what else to make it work. It has been sitting on the shelf and I am thinking about selling it but I want to know for sure what it is.

John in Texas
 
If it is late 88SS it would appear to have been modified some ,bigger ex valves ?, Inlet ports opened up? Some measurements might help. Someting wrong with one tappet adjuster.
 
The front studs are 4-5/8" apart. As I said the valve kit came from RGM years ago but it was for a "stock" but late 88 or 99. The intake valves are 1-3/8". Like you said there is no reference to the R in the casting as far as I have been able to find.
Thank you all for your input on this little mystery, I am sure with your help we will figure it out.

John in Texas
 
Every norton heavy twin's front studs are the same which is why it says nothing toward identifing the bolt pattern size S> M> L
1.4" intake valve is used on pre 750 heads so the only thing to be decided is squishband for spigot 72mm or later no spigot 68mm approx ...or modified?
 
There it is, early (spigot) small bolt pattern. 88SS or 650SS is Norton p/n S650/136. Are the intake ports stock? 28.5mm?
 
It's hard to imagine it could be used with those big valves on spigot barrel?? Intakes look big also?
 
Hortons Norton said:
It's hard to imagine it could be used with those big valves on spigot barrel?? Intakes look big also?
Click to expand...

intake port showing about 31.19mm?
squish showing 74.6mm?
could be a mix of pix?
screen measurements ratios vs real head measurement ratios don't seem to add up to a regular small pattern head.
 
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