This study focuses on optimizing scramjet performance. Recent studies have shown that angling the front wall of the cavity leads to better mixing in hypersonic regimes in upstream injection cases, and without affecting flame stability. This study focuses on the effects of the location of fuel injection in the Forewall and Aftwall slanted cavity configuration in Mach 1.65 primary flow based on various performance parameters with merits and demerits. Employing wall-based injectors, the research evaluates jet penetration, mixing efficiency, flammable plume area, and total pressure loss. Validated using a density-based solver, the simulations align well with experimental data. Notably, Aftwall injector (D) demonstrates superior mixing efficiency, while Upper-Forewall injector (A) excels in jet penetration. Base wall injector (C) emerges as an overall performer with Forewall Injector (B) as second best, showcasing excellence in penetration, flammable plume area, and mixing efficiency. The study highlights the significance of vortices, particularly the Major Cavity Vortex (MCV), in enhancing mixing. It suggests the possibility of optimal injection positions along the forewall which is not possible along the aftwall, while emphasizing the existence temporal variations for the Secondary Vortex. The findings pave the way for exploration of transient behaviors for deeper understanding.