im overheating and loss of power off the line

[martine]

hello ed.im the guy who boughjt a 1966 delta88 425 superrocket from a guy in idaho.his email was vegjam@aol.com.anyways love the car.but im having a overheating problem.listen i added a three row radiator and a tech from mondello performance advised me to get a aluminum water pump with water restictors and that should cure the problem.so i did and all hoses and my timing is dead on.also my fuel and air mixure is prefect.and i flushed my entire system out.nothing seems to work.it doesnt overheat when im driving.only when im stuck in traffic and ideling in drive.i use to have a 65 delta88 and i never had this proble.even though the heat gets up there at 115 in the sacramento,ca area.i was also told that on the driver side exaust there is a coil spring with a weight attached thats supposed to open when the engine gets hot to let the exhaust escape through mufflers.but told it could be rusty and old and that causes the backpressure which in turn heats the intake area up causing overhaeting.do you know what tere talking about.any suggestions.please help.

[Mike Hathaway]

the heat riser is on one of the exaust manifolds,just where the exaust pipe mounts to the manifold,i would spray it with WD-40 or GM used to sell a heat riser spray.Also i would have a radiator shop check the antifreeze for presence of exaust gases-MWH