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1970 Cutlass Supreme 4BBL Quadrajet 350 Rocket, New HEI distributor. I have the car running but I know I have a vacuum leak somewhere based on my current vacuum line setup. I have vacuum coming off the manifold and the advance on the distributor is working but I can't find a great diagram for the proper vacuum hookups. I have the 1970-82 Chilton book but the image is a bit off from my setup. If someone has a good diagram that would be awesome. I will attach a few pictures. I need to get new carb base gasket but want to properly hook up my vacuum lines and test the vacuum to chase down any other leaks that could be on the lines.
Throw away the one-size-fits-none Chiltons and get an original, paper copy of the factory Chassis Service Manual for 1970. Do NOT get a reprint or PDF. The correct vacuum diagrams are in there. And FYI, none of those drawing you posted are even close to correct for your car.
Throw away the one-size-fits-none Chiltons and get an original, paper copy of the factory Chassis Service Manual for 1970. Do NOT get a reprint or PDF. The correct vacuum diagrams are in there. And FYI, none of those drawing you posted are even close to correct for your car.
Thank you I almost bought that service manual. No chance you have a pic of the vacuum diagram out of that book do you?
Throw away the one-size-fits-none Chiltons and get an original, paper copy of the factory Chassis Service Manual for 1970. Do NOT get a reprint or PDF. The correct vacuum diagrams are in there. And FYI, none of those drawing you posted are even close to correct for your car.
I just now bought that service manual off ebay. No worries if you can't get the vacuum diagram
Your car should be able to easily pull 15.5"Hg vacuum w/ a stock cam. Generally, you should expect to see ~17.5"Hg @ idle. A vacuum gauge is a good inexpensive investment - find them at your typical automotive parts/supplies stores. It's nice to have a "T" you can tap into, but not necessary - you can measure vacuum direct from an intake manifold port. NOTE: When evaluating your vacuum, you want a "steady" vacuum reading e.g. vacuum gauge needle does not bounce around.
Good you ordered a 1970 CSM - it's the bible for your car.
Your car should be able to easily pull 15.5"Hg vacuum w/ a stock cam. Generally, you should expect to see ~17.5"Hg @ idle. A vacuum gauge is a good inexpensive investment - find them at your typical automotive parts/supplies stores. It's nice to have a "T" you can tap into, but not necessary - you can measure vacuum direct from an intake manifold port. NOTE: When evaluating your vacuum, you want a "steady" vacuum reading e.g. vacuum gauge needle does not bounce around.
Good you ordered a 1970 CSM - it's the bible for your car.
Thanks for the info! I have t connectors and a gauge. I am going out to start at the manifold vacuum looking for the spec'd Hg. Then I should receive the Full 1970 service manual today to start tracing all the lines and find the leak. I will unhook all and cap and working on one line at a time and make sure they are hooked up as spec'd in the service manual.
I'll bring this to your attention as a forward piece of information you'll most likely need to accommodate into the cerebral cortex as you move forward. During the period (roughly 1969 - 1972) a number of (several) mandated emission control (band aids) standards were implemented. Review vacuum hose routing(s) associated w/ a 350 relative to equipment on the car e.g. A/C or no A/C, etc. Your car (if it remains fully stock) will likely have a TCS (Transmission Controlled Spark) system which employs a valve & solenoid. This is reviewed in the CSM. Sometimes a PO may have removed the TCS (Christmas tree valve) - no worries, many have done this. The point to remember is to make note whether you have the TCS (Christmas tree) valve or it has been removed - since this will determine vacuum hose routing(s).
Here's a link (and there exist MANY more) describing a 455 scenario but it contains enough information for you to read & begin to familiarize yourself w/ the TCS system.
The switch is part of the Transmission Controlled Spark system, which was a prehistoric emissions control system first used on the 1970 cars. The purpose of TCS was to inhibit vacuum advance unless the trans was in high gear to reduce NOx emissions. The wires to the trans plug into a switch that senses the trans is in high gear (a pressure switch for ATs and a physical switch for MTs). The switch is normally closed in all gears except high, which energizes the solenoid in the valve and prevents the vacuum signal from reaching the distributor. In high gear the switch opens, which de-energizes the solenoid and vacuum advance operates normally. Disconnecting the wires at the trans or at the vacuum switch prevent the solenoid from operating, which disables the TCS function and provides vacuum at all times, just like on non-emissions-controlled cars. The valve has a secondary function, which is to switch the vacuum advance from ported to manifold vacuum if the engine starts to overheat at idle or low speeds. This is independent of the TCS operation and is something you want to retain. The thermal function does not require the electrical connection to work properly. When EGR became federally mandated for the 1973 model year, it superseded the need for TCS, so the TCS system was dropped after 1972.
