As Kenny pointed out, beginning in 1961 the M35A1 was powered by the LDS-427. However, it is worth pointing out that while the cargo trucks got the Multifuel then, that was not the case for all the truck models - there were concerns about axle loadings. That being said, I have no problem believing the truck in question currently has a LDT-465 in it.
A true rarity is a military truck with the factory-installed engine still in it.
Best wishes,
David Doyle