351w ping/knock

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Nov 29, 2013 | 07:30 PM

#16

bill06447

Senior User

Joined: Sep 2013

Posts: 373

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From: Marlborough, CT

Agree the lack of egr is causing the pinging. If you're going to leave the vacuum advance off, try lighter centrifugal advance springs. It might be the compromise you need to get that extra oomph without melting valves and pistons. ~Bill

Nov 30, 2013 | 12:05 AM

#17

86f250hd

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Joined: Nov 2013

Posts: 195

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Now can I bend the tab on the springs threw the little hole on the dizzy to put less tenstion on or should I just use lighter springs? I have lots of hei spring kits oand others I'm trying to get a more adjustable advance can

Nov 30, 2013 | 07:26 AM

#18

Franklin2

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Joined: Jan 2001

Posts: 56,980

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From: Virginia

I would not mess with the springs. This is not a lightweight mustang with high numbered gears in it. It's a heavy truck, the timing curve needs to be conservative to avoid pinging. Trucks also like fuel, so I tune my trucks(all my vehicles really) to use the cheap 87 octane fuel. So that requires a conservative timing curve also. Conservative timing curves require the heavier springs the factory uses.

The quickest easiest thing you could do is take the vacuum advance hose off and put a screw in it, and then turn the timing up with a timing light. That will get you going. You can road test it and keep turning the timing up till you run into problems, which will be pinging under load, surging under light load, and if it gets too hard to crank over during a hot restart.