[lkt1954]

Well I am happier than a pig in mud on a hot summer day!!! Just finished putting a cast impeller water pump and new divider plates on my 66 GTO. The plate was massaged to where it was .10 from the impellers. Started and ran the car for 30 minutes and the temperature got to 190/thermostat opened and it dropped to 180 and stayed there. This never happened before 10 minutes and it was at 210--what a change.

Thanks to all for this great thread.

Thanks again
Larry

[Slick]

After modifying the separator plate as directed, I tried three pulley combinations.
1) 6.75" upper pulley, 8" lower. Result, cool as can be, never over 160*, fan noise and drag horrendous. 18.5% OD

2) 7.25" lower pulley, 8" upper pulley. Result, motor warms up to ~190* at idle, low speed, but cools to about 160-170 at 50MPH Fan very quiet. Pre-ignition when at full throttle. 10.3% underdrive

3) 7.25" pulley lower, 6.75" upper. Result, a little fan noise (more than I'd like), but stays at 160* all the time. No pre-ignition. 7.4% OD

It all makes a difference.

1971 GTO
462, 7K3 heads
Summit 2802 cam
iron intake, 800 Q-Jet
headers, stock exhaust
T400/10" converter
3.90 rear
3750 w/o driver
19" factory seven blade flex fan, Olds shroud 4-row factory radiator
No air