Ol Hank developed a backfire issue when idling and also began misfiring. We got the old boy fixed and found and fixed some other issues along the way. #bigblockchevy #chevelle #mortskerepair #twinstickgarage #vicegripgarage #acdelco
I stopped using AC Delco plugs R43, R45 cause R44 are NLA and AC are junk now. I tried NGK, ya not bad but I’m currently using Autolite 306 in my 70 Z/28 and like them. They are a 13/16 plug non extended plug. Get the highest vacuum when setting the idle mixture screws using a vacuum gauge. You will likely need to jet down the primary Holley jets to lean it out. I use a long straight spark plug boot to install my plugs before I torque them. I kept some original long boots from my 87 Grand Nat’l. Mixture screws lean out turning clockwise, and to richen you turn counterclockwise.
