C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette

persistent spark plug fouling

Old 05-16-2019, 09:46 AM
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I was also going to suggest if you have an old carb laying around to pop that on and see if that helps. As far as tuning the carb, I would think that it should be pretty close out of the box for a mild 350. I had the 650 AVS on my 350 for several years and it ran great. I did some tuning with rods/jets but not too much. I also installed it on my new 383 without any adjustment and it ran great. I recently upgraded to a 800 AVS2 on the 383 and it's awesome out of the box. Might be a little rich so my plan it so jet it down a bit.

I also ran into the stumbling block of where to find the tuning/calibration kit and had to have a couple calls to Edelbrock and finally got one. I will post it. At first they sent me the chart for the AVS2 650 (attached PDF). Note that there is no calibration/tuning kit available (which sucks) so you have to purchase all of the rods and jets individually. Using the chart, you have to see what rods and jets you want/need and make a list and buy them. This is what I did for the 800.

For example, using the chart, if you want to go one stage leaner (from base/stock calibration) to number 2, you would need jet 1427 and rod 1449.

Hope this helps. This is fresh in my mind since I have just gone through it.

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Old 05-16-2019, 08:50 PM
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Thankyou.Thats what I was looking for. Kind of strange Edelbrock told me that rods wouldnt help a rich condition.
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Old 05-17-2019, 05:50 AM
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Originally Posted by speedreed8 View Post

I believe thatís a cold heat range racing plug. Probably need a hotter plug to burn off the deposits for everyday driving.
needs a Autolite 3922
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Old 05-17-2019, 09:08 AM
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do you have another carb to swap on for a test? Like the 1406 mentioned above? Borrow one not buy, swapping parts like this is a great way to rule out items as bad.
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