stats/info

Low-tech (early) Kerolox upper-stage engine. ~1.45m overall diameter (intended for 1.875m rockets) (2.24m * 0.64). 0.49m individual bell diameter.

4-chambered engine, with single common combined axial turbopump.

0.67 tons
122kn vThrust
105kn sThrust
326 vISP
280 sISP

Yes, that is with the stock scaling (which nothing is using at the moment due to the LH2 patch); IIRC the actual ISP is ~280-326, so its not the most efficient engine to begin with.

Wikipedia and Astronautix both give 326, yeah. Not incredibly efficient, but reasonable for the era and cycle.

302s seems rather low to me ... is that with the Isp scaling? Those numbers seem much more in line with stock lower stages than upper stages.