Many thanks for the greetings, advices an comments,tclederman, hotshoe36,truckernix,atomarc, 54TOW and TxLaTx.
My language is,in fact,portuguese.But I understand Spanish well.
Hotshoe, the truck is exactly like the one in the link, except that it is 10 yrs. younger. The differences are minimal. You will see them in the photos to be coming soon, truckernix. Sounds really better to measure the gap (hot) in the middle cyls. I'll do it.
Muito obrigado a todos!(portuguese)