I'm about to drop my 455 into the GS. The 350 in the GS now has been converted to GM HEI, which works perfectly. The 455 is a stock 70 with it's original ignition, which I'm going to keep at least for a while. What is the source of power for the coil? Aren't I supposed to use a resistor or something, or is it normal voltage? Thanks, Frank Brooks
Frank, The original coil + wire had a calibrated piece of resistance wire running from the engine harness connector(below brake booster), through the harness, where it is joined by the "R" wire from the starter solenoid, and then to the coil +. When the ignition system is converted to HEI, that wire is removed, and replaced with a plain piece of wire to provide full time 12 volts. Did you do the HEI conversion? If so what did you do to convert it to HEI. Some guys just piggyback a wire near the harness connector. The right way to do it is to replace the wire. We need to know what was done to answer your question.
I didnt do the conversion. The positive wire to the coil is crudely spliced a foot or so from the distributor. I would prefer to unwrap the harness, check it and replace the wire for the coil (I'm detailing the engine compartment anyway). I prolly should get a chassis manual. I tried on ebay and lost. Can you describe the wire to use at the firewall? And I connect it to the wire from the starter exactly where? Or is at the coil OK? Thanks for all your help! Frank Frank
Frank- Did you consider swapping the gears off the bottom of the distributors and running your HEI in the 455? You stated it was working perfectly and this swap would save you some rewiring. If you still want to use the stock distributor, I'll look up where on the wiring harness connector block the feed comes from. I did the reverse of what you're doing and it wasn't that hard. I tucked the original wire from both ends back into the harness and rewrapped with the correct friction tape (don't use adhesive backed electrician's tape). I think your easiest bet is swapping distributors, if that's an option.
Frank, I'll describe how it works. The points would not last very long on 12 volts constant. The ignition system will run 7 volts or so. To start the motor 12 volts is best. When the engine is running, 12 volts flows through the harness connector, through the resistance wire, which reduces the voltage. When you crank the engine with the starter, the "R" terminal on the starter solenoid sends 12 volts, to a point beyond the resistance portion of the wire, bypassing it to deliver 12 volts to the coil. The "R" terminal only has 12 volts during cranking. As soon as the engine starts, and you let the key go to the run position, the coil again gets it's voltage through the resistance wire. Follow the wire back through the harness, and see where it goes. If you follow it back to the harness connector on the firewall, someone replaced the entire wire. If you want to run the points, you can wire in a ballast resistor with a plain piece of wire to the coil positive. Then run a second wire from the "R" terminal on the starter solenoid, again to the coil +. The second wire will only be energized while cranking, and the coil will get its reduced voltage through the ballast resistor for the run position.
Larry, That was a perfect discription. No problem... I understand now. I am planning to convert to breakerless ignition very soon after I complete the swap, including a high output external coil, a stealth system under the cap and and a 12SI alternator. I just think I should get it running in the GS before I attempt that, since I pulled the 455 from a car I drove into the driveway and had to push out, so I KNOW there is nothing wrong with any part of it. Does that make sense? Can I use a high output coil on a factory points system? I threw the old coil away because it was ugly. Any recommendations on a stealthy HEI? :beer Frank
