Most of those bolts are 10x1.25. There’s a couple that are different.
Since they’re discontinued. Get out your thread checker and micrometer then check out the bolt resellers:
ARP
Fastenal
Bolt Depot
Etc
This website shows the part numbers. The page linked below is for a 1986 FJ60. If your engine is different, start over from the vehicle choices at the top of the page.
http://www.japan-parts.eu/toyota/us/1986/land-cruiser-60/fj60lg-ka/4_791420_004_/tool-engine-fuel/1302_camshaft-valve#13951A