The line of G3500 engines brings versatility, uptime, and low operating cost to your gas compression operation. They are equipped with ADEM A3 technology that enables highest performance and safety while maintaining low emissions. Ideal applications for G3500 engines include gas lift, gas gathering, and wellhead gas compression. Cat G3508 gas engine. Ratings: 391-500 bkW (524-670 bhp) @ 1200-1400 rpm are NSPS site compliant capable with customer-provided air-fuel ratio control and aftertreatment or available for non-regulated areas.