the tires pictured above are TSL made by Interco.. I can't make out the exact style or size..
https://www.intercotire.com/tires/ty...truck_off_road
they're famous for the the TSL Thornbird and Super Swamper tires among several others..
they introduced the original Swamper tires in the 60s or 70s
outstanding offroad traction performance but
they are bias ply and not popular for the younger high-speed crowd..
I like the looks of them on vintage trucks because they look more like the bias ply truck tires that were common back then..
they do have a couple of designs that may be to your liking..
Narrow SS TSL
https://www.intercotire.com/tire/126
pictured here on their website on a 67-72 Chevy / GMC something
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another option, also bias ply are the STA Specialty Tire of America
they make a popular offroad tire you may have heard of, the Super Lug
https://www.stausaonline.com/product...t-truck-tires/
they also make a lot of odd sizes, several for 16.5" rim, military styles and sizes, etc..
I have 16" STA Super Lug 9.00-16LT on my 71 K20 Burb - 36.6" diameter!!
listed on this page
https://www.stausaonline.com/tires/sta-super-traxion/
those are TSL Thornbirds on the K1500 behind the K20
I plan to eventually buy a set of farm skinny's for my 65 C20 to look like these original sizes..
STA makes a lot of this variety of tire, highway tread up front, lugs in the back
Good Luck!