79 Caddy Overheating Issues
I am still new to this board and appreciate the honest answers and helpful attitude all of you have. This is not necessarily a hot rod question, but is about a racing application. I have a pretty good background, especially with SBC stuff, but am running a 79 caddy with a 425 in an entry level dirt track class. Because most rounders don't mess with caddy stuff, I thought that maybe you guys might have some ideas. Here are the details:
-425 stock compression
-shimmed SB valve springs (reduce float above 4000)
-Big 4 core radiator
-Q-jet with choke removed, larger primary main jets/matching rods, slight mods on secondary rods
-Notched plenum wall below secondaries, cast iron intake
-Timing at 10 @ 1000, 28 @ 3500+ (total advance)
-Stock, open exhaust
-High octane pump fuel with 20% racing fuel mixed (recommended by the other stock class racers)
-I removed the thermostat "button" and put the base in to act as a flow restrictor
-RPM: 5500-6000 peak at end of straights
The problem that I have is the temp. If I sit in the staging area too long, as with a long yellow in the race prior, it starts to get hot pretty quick. (250 - 260) If I can get on the track right away, it is a little happier, but will still get hot before the end of the race. I think that I'm getting enough fuel, and it seems like it has decent accel out of the corners until it gets hot, then the valves start to float a bit easier. I am running with water wetter and staright water, also suggested by the boys at the track.
The temp gauge is sure distracting when the needle gets to the up side. Best finish has been 2nd in the feature, and I'd sure like to figure this out so that I can worry about going faster instead of runing cooler.
Any thoughts or help would be greatly appreciated.