The original brochure can be found here: http://brochures.slosh.com/
It appears the standard size was E78-15B which converts to a P195/75R15
Some of the optional sizes were 7.00-15C, 6.50-16C, 10-16.5C, G78-15B, H78-15B, and L78-15B.
http://www.turbinecar.com/tires.htm has a very thorough list of conversion tables to obtain modern size equivalents.
P235/75/R15
215/75R15
Stock size 235/75 R15
per vehicle specs on a 1998 gmc jimmy 4x4, the correct size tires are 235/70/15
LT235/75 R15 (Canada)
3/4"
p235 70/r15
call AAA
235/70/15, 235/75/15, biggest without a lift 30x9.5x15
OEM tire size is 205/75-15. You can install 215/70-15.
tire size for 1959 gmc 150 hydramatic need tire size vehicle most likely came witrh from factory
through the tire wells