The precision-machining of injection molds for disposable wax patterns intended to be used in investment casting of complex superalloy aerospace components is a costly and time-consuming procedure; thus, making this method particularly unlucrative for unit or limited production runs. Yet, additive manufacturing of casting models can be more suitable in this situation. Our work, then, is to explore the feasibility of using the Masked Stereo-lithography Apparatus (MSLA)-based 3D printing technique to make a unitary experimental investment casting pattern of a jet fuel distributor unit made of Inconel 718. The model is first designed with the aid of numerical casting simulation. Then, the approved model design is 3D-printed, and the operation outcomes are discussed and analyzed. The simulation-assisted pattern-design iteration has granted to a porosity-free cast with a microporosity index and a shrinkage deformation less than 0.54% and 6.6 × 10−2 mm, respectively, altogether with a satisfactory yield of 69.17%. MSLA 3D printing has led to a cost-effective, high-quality pattern with a yield of 88.6% thanks to proper preprocessing settings including calibrations, and proper slicing design and refinements. The implemented process was found, however, to be perfectible through some technical adjustments we discussed briefly at the end of this work.