i realize that as you increase your ignition power, you need to get better spark plugs and increase the gapping.

so here is what i am getting...

*Mallory VI-AL Digital CD ignition box: 520V to coil, spark output 135 millijoules.
*matching billet aluminum distributer
*51,000 Volt Mallory coil
*MSD 8.5mm Superconductor Wires

for all of you familiar with the MSD 6-AL box, it puts out less power than the mallory unit, and sucks up more (because it is analog instead of digital) so that could be slightly comparable.

i have always had good results with NGK iridium plugs on all of my other cars (1989 5.0 mustang and on the 1996 4.6L GT) and am wondering about those on a SBC...

i also know on here everybody preaches AC Delco, but they dont offer iridium plugs (at least that i can find).

so...

1. What plugs?
2. What heat range? (stock, or not?)
2. What gap?

 

I run Autolite Racing 3934's. They are a 3/4" reach plug (my heads require that size plug) and a lot shorter for headers. I would start out with a .040-.045 gap.

 

what ignition system are you running?

 

I have an Taylor HEI distributor w/ 50k volt coil and upgraded module, 8mm jegs wires.

 

any other suggestions?

 

anybody?

 

I run AR133s. they are step colder than stock.

 

what ignition setup do you have?

 

MSD Billit Dist, MSD Blaster SS coil, Crane Hi6 box, MSD 8.5mm wires.

 

I been told that 045 is good as gap with a newer ignition system.

 

you could probably use a plug one step colder than stock based on your
mods, but it's tough to say without seeing your old set as a starting point.

0.040 - 0.045" is a great starting point for gap. There is enough energy
available from the coil to jump such a gap. You could probably get away
with up to 0.060" depending on the DCR of the motor and cylinder pressures.

Run the most gap possible without the risk of misfire, or mechanical interference. You have to know how to read plugs to get an idea of which
way to move the gap. Dyno's and track testing are great for getting this
correct.

 

what is the benefit of running a step colder?

 

Not much unless your current heat range is causing the electrode to warp
and open up due to intense heat, or pre-ignite which is deadly to the motor.

 

until i am satisfied with the tuning of my carb, i am going to cheap out on plugs for a while anyways, then when i get it dialed in, i will get some big buck plugs.

 

Just so you know, there's no need for big buck plugs unless you are concerned
about maintenance life.

A set of $40.00 plugs will do the same thing, except last an additional 10,000 miles.

 

i dont know if i toally agree with that. i have always had better results with iridium plugs over the cheaper platinum plugs on most of the cars i have worked on.

 

Let me tell you a little tuning secret...that's not really a secret.

Copper core plugs are the best electrical conductors. Most race engines
use copper core plugs to make the ignitions more efficient.

The only set back to using copper core is that they wear down faster,
and you need to replace them sooner.

If you were having bad luck with copper plugs, you might have used the
wrong projection, heat range, gap, or a combination of all.

Here's a link to some of the most common race plugs:

http://inpcars.com/spark-plugs1/172.html