Timing on truck

[ChevyC1500]

I put my vortec L31 heads on along with a edlebrock RPM and my lunati cam 262/268 and I needs help with my timing. Where should the timing be at? We have it around 20 it's still making that popping noise when I get on it.

[88blackchevy]

Just to clarify you are talking about base timing?

[ChevyC1500]

Yes.

[SUBURBIAN]

We needs to know a little more about the setup. Ignition system? Computer-controlled engine?

[Doober]

If it's popping out he intake you have too much advance, a vacuum leak, or both. If it's carbureted you should be good with around 12-25 degrees. If it's TBI then the computer requires a specific timing setting (with the tan/black stripe wire disconnected), most TBI engines have a base timing of 0 and everything is controlled by the ECM.

[ChevyC1500]

@ doober where is the disconnection for the TBI ? We have it set on 8 right now, hasn't been making the popping noise.

[Doober]

Mine is under the plastic cover on the passenger side of the firewall. If you remove it you'll see the fuel pump relay and a couple junction boxes. When you unplug it the service engine light will come on but that's normal. I sometimes set them just a couple degrees over the recommendation because in my experience it's given the TBI engines a little more throtle response & just a hair more oomph.

[ChevyC1500]

Oh okay. Sweet thanks man.