Tonight, I put on the new hi-flow water pump. My old water pump was rated at 85 gpm, the new pump at 130 gpm (!). The kit came with a new crossover pipe with dual thermostats like the later model 6.5 turbos. Dual thermostats are needed to handle the increased flow rate from the pump. The thermostats provided in the kit are Robert Shaw super-duper special 'stats set at 180 degrees. The kit came with a new bracket for the throttle linkage. I also purchased a specially calibrated fan clutch that operates at a lower temp than the stock clutch along with a 9 bladed fan. These kits were obtained from
Kennedy Diesel
Jerry Hedger from Independence Hummer in Charlotte, NC is sending me a kit that uses the currently blocked off water jackets on the two rear cylinders. He uses very high quality components in his kit, including stainless steel braided hoses. This kit fits both NA and Turbo engines. In the stock setup, coolant is not circulated well or at all at the rear cylinders, as evidenced by both of the rear cylinders in my old heads having cracks between the valves. The addition of the kit will allow coolant to circulate in the rear of the engine and help to keep head temps down. I suspect after making these cooling upgrades, I may have to do like the big trucks and close off the grill to let the engine warm up in the winter!
I'll post some pics of the new parts in a day or so.
Scot Smith
1994 HMC4, Locked
"They're right, Wider IS Better..."
Southern Axle & SteeringRemanufactured Driveline & Steering Parts for Hummers