Sorcerer (1977)

Four desperate men on the run in South America agree to transport dangerous nitroglycerin -- so unstable that if it is shaken or jarred the explosion will destroy the trucks it's carried in -- via a rough overland route.

As with The Exorcist, Sorcerer is best when it's played straight, in the more naturalistic moments of wind-tossed bridges, desperate faces or quiet drinks, and at its utter worst in moments of stylistic excess, such as Roy Scheider's traumatic flashback/dream sequence.

The Tangerine Dream synth soundtrack is dated and oppressive, while character development is wildly uneven; the attention given to the backstory of Serrano (Bruno Cremer) is interesting but results in no payoff. Conversely, it seems bizarre to include a middle-eastern terrorist with no exculpatory background or rationale. But the central journey so tense that it all still works.

Amazing snipped from the Wikipedia entry:

During a sequence involving the detonation of an enormous kaoba tree, Friedkin was faced with a problem of inadequate explosive power. Initially, Marcel Vercoutere, a special effects man who previously worked with the director on The Exorcist, was to be responsible for the explosion. However, it did not achieve the required effect and barely damaged the tree. This prompted Friedkin to reach for the services of an arsonist hailing from Queens, New York, going by the pseudonym "Marvin the Torch", who arrived at the Dominican Republic three days after the call and utilizing flammable materials obliterated the tree in one take the following morning.