by Ctjeff Fri Sep 20, 2013 5:15 pmHi guys,
My 1964 g10 250 inline 6 is still running hotter than I would like. It has dual 2 bbl carbs, offy intake, stovebolt headers, dual exhaust and a mild cam. Its been in the 60-70f range outside and I am still 188- 200f in normal driving (sending unit located in the head). I have a new aluminum radiator (American eagle 2 row 1" tubes 17.5 h x 17.75 core), 160f tstat, bellypan in place with the front lip of the pan bent down 3" below the bumper to act as a scoop. All of these changes have helped but I think I should run a little cooler in these temps. I worry that next summer when its in the mid 90F I will be back around 230F plus. I am thinking about replacing my water pump pulley from a 7 1/8" to something around 6 1/4" but can't seem to ID or locate one. My harmonic balancer is 6 3/4 OD so right now I am under driving the fan and water pump. So at 1000rpm engine speed my fan/pump spins about 950 rpm. If I go to 6 1/4" on the fan/pump I will spin the fan/pump at 1080. When I am idling and the temp creeps up I can lower it by revving to 1500 rpm so I know that if I could slightly overdrive the fan/pump it should help across the board.
So my question is does anyone know where to find a 6 1/4"ish OD, 2 5/8" deep water pump pulley that fits the 250? Part numbers? Does such an animal even exist? I have read where some guys have overdriven the fan/pump but wasn't sure if it was on a SBC or straight 6.
Thanks in advance....
My 1964 g10 250 inline 6 is still running hotter than I would like. It has dual 2 bbl carbs, offy intake, stovebolt headers, dual exhaust and a mild cam. Its been in the 60-70f range outside and I am still 188- 200f in normal driving (sending unit located in the head). I have a new aluminum radiator (American eagle 2 row 1" tubes 17.5 h x 17.75 core), 160f tstat, bellypan in place with the front lip of the pan bent down 3" below the bumper to act as a scoop. All of these changes have helped but I think I should run a little cooler in these temps. I worry that next summer when its in the mid 90F I will be back around 230F plus. I am thinking about replacing my water pump pulley from a 7 1/8" to something around 6 1/4" but can't seem to ID or locate one. My harmonic balancer is 6 3/4 OD so right now I am under driving the fan and water pump. So at 1000rpm engine speed my fan/pump spins about 950 rpm. If I go to 6 1/4" on the fan/pump I will spin the fan/pump at 1080. When I am idling and the temp creeps up I can lower it by revving to 1500 rpm so I know that if I could slightly overdrive the fan/pump it should help across the board.
So my question is does anyone know where to find a 6 1/4"ish OD, 2 5/8" deep water pump pulley that fits the 250? Part numbers? Does such an animal even exist? I have read where some guys have overdriven the fan/pump but wasn't sure if it was on a SBC or straight 6.
Thanks in advance....
