Check this out
http://www.oldgmctrucks.com/page0157.html I found by clicking the pics of the trucks it will take you to more info
http://www.oldgmctrucks.com/page0005.html
By the way the 350-24 conventional trucks had a 248 c.i. 6 and 4sp as standard equipment.
How about that 6.0 quake today in remote AK ?