400M Stock vs Crower/RPM vs Crower/CHI
This graph illustrates the difference between the stock (baseline) 400M and the runs made after installing the Pro Comp heads, Crower cam and both intake combinations. In stock trim, the 400M produced 265 hp and 412 lb-ft of torque. Note that these occurred at a very low engine speed (the 400M exceeded 400 lb-ft at just 2,000 rpm). After the installation of the Pro Comp heads, Crower cam, and RPM Air Gap intake, the peak numbers jumped to 489 hp and 502 lb-ft of torque. Swapping out the dual-plane for a single-plane CHI intake and Dominator carb resulted in peak numbers of 529 hp and 506 lb-ft of torque. Note that the dual-plane intake offered more power up tot 4,300 rpm, but fell off thereafter to the single-plane combination.