Why could a 4-cylinder high-speed turbodiesel be a good alternative to a V8 in hot-rods?
Even though the hot-rod culture is more widely associated to gasoline-powered engines such as the Ford Flathead V8, which could be sourced not only from passenger cars and light-duty trucks but also from medium-duty trucks considering all that "there is no replacement for displacement" philosophy, obviously this is not the only possible approach. Considering the consolidation of Diesel engines as the favorite option among most commercial operators, including the retrofit into older trucks fitted originally with a gasser V8, it could be easy to presume the viability for a similar phenomenon to reach the hot-rod enthusiasts too.
Even though the preference for V8 gassers remains strong in modern hot-rodding, the availability of 4-cylinder high-speed turbodiesel engines being easier on most markets outside the United States and Canada could lead to an increasing interest on those, not to mention the hot-rod scene originating in a counterculture movement which could be related to the recently-widespread political targetting of both large-displacement engines and turbodiesels in general as an environmental threat. Sure the power ratings of most 4-cyl turbodiesels might not be so impressive compared to a stereotypically all-American small-block V8, the torque curve won't render a relatively small turbodiesel so unfavorable compared to a naturally-aspirated V8 or even mildly-boosted through a belt-driven supercharger, even if they feature nearly twice the displacement of their turbodiesel counterpart...
The fitment of the Cummins ISF2.8 engine in the latest versions of the Brazilian Ford F-350 and its regional derivative F-4000 between 2014 and 2019, for which a V8 wouldn't be cost-effective, could seem at first only as a desperate attempt. However, considering fuel prices and consumption while keeping the comparison to the V8 gasoline-powered, resorting to this engine at a regional level was more suitable to the market conditions than going for a V8 PowerStroke turbodiesel fitted to their American counterparts. So, to keep things in proportion, when applied to a truck both a V8 gasser and a 4-cyl turbodiesel might not seem so fancy at all and being considered more for their utilitarian approach, and therefore it's also quite down-to-earth to focus on similarities on other applications, which can include hot-rods too.