According to Dan's ledger, after his apprenticeship where he made $15/day working 5 to 6 days per week, he is making $40 per day - about ten times what the average blue-collar worker was making at the time. And that $40 would equate to around $776 in 2021. This astronomical amount for the time reflects the danger of the job and the probable fact that few men would be willing to take the job.
The airplane Sam flies to Mexico with the "soup" is a Fairchild 24C-8E, registration NC16350. Fifty of this variant were made in 1936 out of a total of 2,232 for this model from 1932 to 1948. List price new in 1936 was $5,390 (about $107,000 in 2021). This particular aircraft also appeared in the film Danger Flight (1939).
The first "torpedo" for use in oil wells was patented in 1864. The first torpedoes used gunpowder until nitroglycerin - as shown in this film - was discovered to work better as it was a much more powerful explosive. The explosion breaks up paraffin way that clogs a well and also fractures the surrounding rock to allow oil to flow easier. Modern hydraulic fracturing (fracking) has almost made the use of torpedoes obsolete. According to an article in the September 2007 edition of The Petroleum Age, the last torpedo using nitroglycerin as detonated on 5 May 1990.