Plug question
Plug question Im at a loss. I dont know if Im over looking something. Here's what going on. I built a 406 SBC gen 1 and its running. Sounds good, no smoking. I decided to pull the plugs just to look at them amd the outer 4 cylinder are running rich. They dark and dry, not wet. the inner 4 plugs are grayish. Look right, but the outers look rick. What do you guys think is going on?
Teching In
Joined: May 2011
Posts: 42
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That condition is due to intake runner length differences between the four outer and four inner runners. Comp Cams now offers a line of 4 profile cams that address this issue. These cams are ground with one set of profiles for the four outter cylinders and a different profile set for the four inner cylinders. This has been a well kept secret in NASCAR for years and only recently has the technology been offered to the car guys. Here is a great article on Engine Labs which explains the issue.
http://www.enginelabs.com/engine-tec...ar-technology/
http://www.enginelabs.com/engine-tec...ar-technology/
Last edited by TheJDMan; Feb 4, 2014 at 05:07 PM.
