SR20DET red top vs black top - Nissan Forum | Nissan …
The valve covers are different colors (obviously) and the blacktop is a newer engine (96-98 I think) where a redtop was produced from 91-93. The S14 blacktop has 20 more HP. It has VVT, a different turbo (T-28) and low-port rather then high-port intake design. The second gen of the S14's came with T28 BB turbos.