Thanks for answering people, i think i have a special kind of distributor because i do not see a coil, it might be inside the distributor.
I would like to show you some pictures of my distributor so that you can tell me what kind is it of.
<<Do you still have that 84 octane leaded fuel?>> Yes, we still have that gasoline here.
<<Is the 97 octane unleaded still available?>> Yes, we have 84, 90, 95 97 and 98 octanes gasoline
<<what fuel are you running in your K5?>> Currently I am using 90 octanes gasoline unleaded, it is working fine, because with 84 octanes leaded the engine tended to tremble.
<<What altitude are you operating at?>> Well, i am using the truck only for small trips with friends, some weekends. I drive it with light foot, i don't like to floor the accelerator pedal because here in Peru gasoline is expensive US$ 4.33 per gallon.
I would like to find some trick that help me to save some fuel, because my truck has a low mileage, 12.5 miles per gallon.