Pinging 427
Thread Starter
1st Gear
Joined: Feb 2011
Posts: 1
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Pinging 427
I hope it's all right if I post a question about my 55 Bel Air with a 68 427 385 Horsepower. I built it factory stock (10.25 compression), single quadrajet, mild Isky hydraulic lifter cam, headman headers, Hays Stinger electronic ignition. I use 91 octane gas and Lucas octane booster. AC R42XLS plugs. Retarded timing. Still pings. Supposedly the "book" calls for AC 43N spark plugs. How can I cut this ping problem without tearing down to lower compression?
Team Owner
Joined: May 2001
Posts: 87,337
Likes: 1,590
From: Western NY
You mention "retarded timing", but do you mean the timing at idle, or the rate of mechanical advance in the distributor? You may need to have the distributor re-curved, with a slower rate of mechanical advance, and also might want to install an adjustable vacuum advance canister (if they're still available).
Le Mans Master
Joined: Mar 1999
Posts: 5,398
Likes: 985
From: Itasca IL
Search my threads in the C1/C2 forum for how I've addressed this on my L-68.
In my experience, there is no way to make a stock, mild 10.25:1 427 run on pump gas with a stock advance curve and vacuum advance connected. It will always ping at part throttle and between 1500-3000 RPM.
I have the B10 vacuum advance can (long discontinued, but matches the OE advance exactly), and 12 degrees initial timing with a centrifugal advance that STARTS around 2300 and comes all in at 3500. I had to make my own springs and do a lot of testing to creep up on this configuration. Total centrifugal is limited to about 32-33 degrees (very conservative).
If your distributor advances as quickly as the original did, it will ping like crazy.
In my experience, there is no way to make a stock, mild 10.25:1 427 run on pump gas with a stock advance curve and vacuum advance connected. It will always ping at part throttle and between 1500-3000 RPM.
I have the B10 vacuum advance can (long discontinued, but matches the OE advance exactly), and 12 degrees initial timing with a centrifugal advance that STARTS around 2300 and comes all in at 3500. I had to make my own springs and do a lot of testing to creep up on this configuration. Total centrifugal is limited to about 32-33 degrees (very conservative).
If your distributor advances as quickly as the original did, it will ping like crazy.
