It turns out the primary throttle shaft was twisted and the throttle plates were a bit corroded. So I got some new plates and a new shaft. Installed the .031 nozzle and 72 jets along with new plugs. It still didn't want to idle below 1000 rpm's yet but it would at least idle so I could check the timing. It's too loud with the headers and the muffler inserts so I need to switch to the water cooled exhaust. But the hesitation is gone and it runs strong. It was either breaking up or I was getting a sudden vibration from the driveline or pump at the higher rpm's so I couldn't stay in it. I think it might be the HEI because the wire harness only had either 14 or 16 gauge wire in it so I ran a new 12 gauge wire to the HEI and need to recheck it. I'll try opening the secondary throttle blades a little bit to see if it helps the idle.
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69 Z28 JL8 4 wheel disc brakes - being restored
09 Silverado Z71
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