Finished the install for my stgII LS6 heads and CC 222/224 0.566/0.568 112LSA cam . I have a few questions if anyone can answer:

1. Car now runs at around 198deg.F with Dexcool, could this be from old head gasket debris left in the block and clogging the radiator ...or/ new MLS head gasket?

2. Car idles but if I rev and let off the throttle, the revs will drop too fast and die. Will the PCM "fix" this over the next 200miles or do I need to get it tuned?

3. Power (SOTP) is lower than what I expected. Could this be due to incorrect pushrods (7.400")? The LS6 head is only shaved 0.010".

Thanks for your help... I appreciate it.

 

Well.. I've had a "few" H/C setups on my car, so I'll chime in.

1. Check to make sure you have ALL of the air purged out of the coolant system, this will make your car run warm. Btw... 198 isn't too hot for stock thermostat and waterpump.

2. If you are on a stock tune, you will probably have that problem.. especially on a vette. In my experience, the vette's are a little picky on the idle deal. Drive it some, but you'll benefit from tuning.

3. That pushrod length is fine for a .010 mill on stock lifters. Going back to the tune... that's when you'll realize your true power. Also... I'd be afraid to give it too much hell before I stuck it on the dyno to verify the A/F ratio.

 

Thanks Gomer!

1. how can I get all the air out of the system? I just thought it worked its way out by itself

2. Damn vettes! guess I will have to have it tuned...cant really drive it like it is and have to restart it about 3 times whenever I come to a stop sign

3. Yeah I should know better... got on it a few times HARD (to rev limiter ) now just to see how it would pull. Will be careful now....

anyone else care to chime in?

 

The C5's are not too bad for trapping air since the res. is located higher then the motor. You could however crack the front 10mm vent pipe bolt and relieve some air.

I also agree that the tuning is everything. The idle problem you are having is normal. The motor needs more air at idle. The throttle angle is controled by the PCM and must be changed with tuning. Sometimes we will put a small 1/8" hole in the throttle blade, but I wouldn't do it until the tuning is done.

How did the car run for coolant temps before? The tune should get the fans set to come on earlier. The other remote issue is the installation of the head gaskets. If installed wrong they can cause overheating problems.

What injectors are you running?

 

An important step on a Vette is an idle relearn.Also the idle should be turned up with tuning.
If you are throwing any codes it could be putting your cae into limp mode which pulls out timing.
Another thing to check is that the spark plug wires are on all the way.1 loose one can lose 30-50hp.