UPDATE: **SOLD** Was $150.
Paul spotted this hi-compression head designed for high altitude engines. As I understand it, the “High Altitude” option had a higher compression ratio of 7.4:1, compared with the stock ratio of 6.9:1.
“Hi compression Hi altitude Head for the tough Hurricane 4 motor . It is complete with valve train and has been freshly resurfaced . If you spend time up on the rim or any other place where altitude could be an issue for full performance then this is the answer for you .
Thank you for looking . I also have other 134 cu in Hurricane 4 parts available upon request”
Are there any external indicators to these heads?
There is a”7.4″ cast in the corner that I see in the near corner in the picture. Now we need to look at a regular head.
The part number is to the right of the 7.4 embossment. 648830 I can read. If someone has a CJ-3b Parts manual, it will have the part numbers for the standard head and the optional high altitude head.
I don’t have time to look through this at the moment, but maybe this page will help: https://cj3b.info/Hurricane.html
Part number as for cylinder head assembly shown in Feb. 1962 parts book: 800572-6.9 to 1 ratio under 5000 ft.
649172 7.4 to 1 ratio over 5000 ft. And 800569- 7.8 to 1 ratio over 10000 ft.
I also checked my Fc parts book the 648830 head is not listed as a part number there either.1964 Fc parts book.
Here is an old listing on ebay with the casting number:
https://www.ebay.com/itm/JEEP-amp-WILLYS-1950-66-JEEP-1967-70-4-CLY-CYLINDER-HEAD-CASTING-648830-/181239237437?nma=true&si=ZIU3NMm7o3u707I8bAWAWNpxkPo%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
And a current one:
https://www.ebay.com/itm/JEEP-WILLYS-1950-66-JEEP-1967-70-4-CLY-CYLINDER-HEAD-CASTING-648830/112791472292?_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D50526%26meid%3D5e476d1e473e40c79ae71200ca789fde%26pid%3D100011%26rk%3D1%26rkt%3D1%26sd%3D181239237437%26itm%3D112791472292&_trksid=p2047675.c100011.m1850
And a mention from Hemmings:
http://clubs.hemmings.com/wocv/willywilly/willywilly.htm