Spark plug gap?

**Kitch** · 05-13-2018

So with Vortec heads and TBI injection what spark plug gap do you guy's use?
I see Vortec head spark plugs like the AC-Delco R44LTS6 have a .060" plug gap but TBI head spark plugs have .035" gaps.
I'm assuming this is related to the ignition system, so if I'm using a TBI style ignition I should use the TBI plug gap on the plugs for Vortec heads?
I'm actually running an MSB billet TBI dizzy, Pertronix ignition coil and MSD leads.
I've got some weird knock count issues that I'm trying to figure out and I thought I'd try a different spark plug (currently running NGK BPR5EFS).
I've also just ordered some AC-Delco R43LTS6 plugs so I can try a slightly cooler plug.

**Fast355** · 05-13-2018

Originally Posted by Kitch

So with Vortec heads and TBI injection what spark plug gap do you guy's use?
I see Vortec head spark plugs like the AC-Delco R44LTS6 have a .060" plug gap but TBI head spark plugs have .035" gaps.
I'm assuming this is related to the ignition system, so if I'm using a TBI style ignition I should use the TBI plug gap on the plugs for Vortec heads?
I'm actually running an MSB billet TBI dizzy, Pertronix ignition coil and MSD leads.
I've got some weird knock count issues that I'm trying to figure out and I thought I'd try a different spark plug (currently running NGK BPR5EFS).
I've also just ordered some AC-Delco R43LTS6 plugs so I can try a slightly cooler plug.

I ran M42LTS marine Vortec plugs in my G20 with Vortec heads. I had accel cap and rotor, accel 300+ race wires, accel super coil, MSD 6A box and gapped my plugs at 0.060".

**S.O.B.B.** · 05-13-2018

I had the same thought.not vortec related but engine spec not same as oe for the system . Originally I was running delco plugs gapped at.035 because that's what the tbi system used.but. I changed the gap to the engines spec of .060 rather than the systems spec.I did notice a small a small difference at startup.less cranks to run.not sure how much diff it makes but i would think the burn would be more complete.