Been having some mechanical problems with my 64 (327-300) and was hoping to get some troubleshooting help.
1. I used some lead substitute with my last fill up. I have only filled the tank in my car maybe three times since I got the car back in May. I thought I would try out some lead substitute. I have never checked my compression and have no idea if my engine has been rebuilt or modified to run modern gas. I thought it might help performance and it is about 1/3 the price of the octane booster I had been using. From ½ to full throttle, I noticed increased power, torque, etc. However, the car idled very rough, if at all. It died about 10 times in 30 min city drive (lots of stop lights). Couldn’t seem to keep it running.

Got it home and tinkered with the carb and got it to idle at about 1000 rpms, but I can clearly hear it missing. Is the lead substitute to blame? It was idling okay before. Should I discontinue its use, or deal with the rough idle to enjoy the better full throttle acceleration?

2. Noticed two puddles instead of the usual one under the Vette the other day. I have power nothing, and it didn’t smell like gas, so I examined the coolant system for a leak. Found that the coolant was coming out of the “overflow tube” from the overflow tank. For clarification: the tube that comes out of the TOP of the overflow tank, not the one attached to the radiator. I assume this is there to drain extra coolant out of the overflow tank. Should I be worried that I have a lot of coolant coming out of mine? It hasn’t run hot. Could this be a sign that my radiator is plugged up somewhere? I plan on flushing the fluids and replacing the two main hoses this fall/winter.

 

My 65 327-300 runs fine without any additives with just premium grade gas. I would do away with the additives with that engine. also that idle is way too high for normal running.
As for the coolant, check to see that your puke tank is only filled half way as designed. If you overfill it, it will puke. If the engine was not running hot on your gauge and the overflow tank was only half full, I would check the actual engine temp wint an IR gun at the house coming off the thermostat housing to see is the gauge is accurate.
Don

 

I have seen several occasions where the Pb add just laid in the fuel bowls, never made it to the engine.
Suggest removing both bowls and havin a look see. Bill.

 

Lou64 If your flushing the cooling sys. unscrew the block plugs on each side, lower part of the block. They could be stopped up with sediment, so be prepared to poke into them. If you don't know how old the heater hoses are, replace them and flush the heater core at the same time. Be careful taking the hoses off the heater core ends. Slit the hoses, and peel each one off carefully so you don't damage the solder joints on the ends. As far as how the car runs, I agree about not using the additives. Do you know how old or new all the plugs, wires, cap rotor etc. etc is? What about your fuel filter. Can the previous owner be trusted in what they have told you about the state of tune is for the motor. You basically need to zero base everything so you start fresh and develop a trust in the car. Dennis

 

Previous owner has been dead for seven years. You can read my personal info for more details.

The plugs probably need replaced...have some and even thought about putting them in yesterday, just didn't have time. Ran through much of the gas today and refilled about half tank. Ran much better. Turned the idle back down and it sounded normal again about 700 rpms. Taking the lead substitute back to Autozone (I bought a few of them).

The heater hoses look good. Why should I replace?