What gap should i set my new plugs at? Most of the time I get the pre-gapped plugs but i figure these are different. Or are they fine the way they are?

 

i believe i just used the stock gap, not sure about your engine tho

 

Set them at stock, and then bump them a little to fine tune. Stock should be around .35 or .40 depends on the year. I set my plugs at .25, but then again, I'm still stock and a smaller motor.

 

I'd go .45 since your gonna be running a hotter ignition

 

Bigger wires, go stock gap, if you have a coil & ignition box, go .010 over.

When you install the plugs, put a piece of tape around the bottom of the socket closest to the ratchet. Mark a wide line with a sharpy to show which direction the gap opening points to. Put the plug into the socket so the gap lines up (as close as it will) with the line. Install the plug and if it lines up to roughly straight up leave it in, if the line is pointing down, pull the plug, try it in another cylinder later & try the next plug. Doing that can yield up to 2-3% improvement in power. Minor gain but it only takes time, will give smoother idle and very slight gain in mpg. FYI, you have just indexed your plugs

 

+1 On indexing. And Blue, never trust pre gapped plugs.

 

so indy or metal....

is that with the ground on the top closeest to the head and open towards the piston?

 

Its so the gap is pointing to the center of the chamber or bowl whatever you wanna call it. So the spark is closer to the air and fuel

 

You want the ground strap point down, the gap opening pointing up Have a pic on my site somewhere,,,

 

Heres how I set up my 3923s in my eddy hds
FYI, pic upside down, head was resting on intake ports on my bench