I have a 1968 Gto with the original stock 400 with 10.75 to 1 cr. I have replaced the distributor with an HEI (original dual vacuum dizzy replaced with another points style dizzy before I purchased the car). I have rewired the HEI and have 12 volts at dizzy.My initial timing is set to 10 degrees,vacuum canister disconnected and getting pinging at part throttle. I changed springs in the distributor to the gold ones.Need help!Allen
The vacuum and mechanicle abvance may need to be limited. Does it ping with vacuum disconnected and plugged. Initial + mechanicle should be around 32 degrees. Then vac advance limited to 8 to 10 degrees. These are generic settings for a hi compression engine. Use highest available octane fuel.
Bull Nose Formula/ 461/ Q-Jet/ TH400/ 3.08 8.5 / R44TS.
Using 93 octane fuel,Ithe vacuum advance is disconnected and plugged off,I am thinking maybe to much mechanical timing.I have installed the gold springs as Lars suggested but not sure where to go next.
The gold springs are the lightest springs, did you try running stockist heavy springs to bring the timing I later?
78T/A 4-SPEED Marty blue 400/milled 6x-4's/268H,comp roller tip rockers/ performer Q-jet/RA manifolds 2.25" exhaust with x-pipe/ mine since '99 3rd & final owner as long as I'm alive. 77 T/A sold 85 Monte Carlo SS sold 83 Mustang GT sold "Let me tell you what Melba toast is packing"