TomM 25 Report post Posted September 10, 2018 I found a box in the trunk of my rolling shell last year when I purchased the car, I kept it but never knew what it was - until today: two vacuum ports and two electrical pigtails, four wires. This weekend I was chasing vacuum lines and I found two (one large/one small dia) that go through the driver's side firewall - both end 8" on either side. I think they may have gone to the electronic spark controller. I've only driven the car around the block a few times but seems to be running fine - period correct 302/2V. I don't see a lot on the internet on these things, do I need this device? Thanks, Tom Quote Share this post Link to post Share on other sites
unilec 57 Report post Posted September 10, 2018 Its hard to say what has been done to your car over the years, but it may have had an early system along the lines of these systems. I know it a vette, but it may give you an idea. https://www.autozone.com/repairguides/GM-Corvette-1963-1982-Repair-Guide/Emission-Controls/Transmission-Controlled-Spark-TCS-System/_/P-0900c152800836b0 Quote Share this post Link to post Share on other sites
Mach1 Driver 560 Report post Posted September 10, 2018 there were also some mandated add-on smog control boxes in the 70s (in some states) that had vacuum and ignition wires going to them Quote Share this post Link to post Share on other sites
EastYorkStang 63 Report post Posted September 16, 2018 Any pictures of it ? Quote Share this post Link to post Share on other sites
