CO2 is somewhat of an "annoying" product which is used by both sides in such a discussion: yes, it is part of nature's cycle (for instance trees use it), but in the wrong quantities, it is dangerous to life (try breathing it!). So it does make sense to to control how much there is an the atmosphere, by controlling how much humans produce.
To answer the original question, one way that could work (depending on local laws) would be to install a complete modern drivetrain in your truck: a popular exemple could be the LS series of engines, many parts/harnesses are available for this swap in many old vehicles.
