Hey guys this might be a little stupid but how do you when you should run three range colder plugs and a 160 thermostat. And another question is summertime is coming up and i want to run NGK iridium plugs, but i dont know what type to run, an even colder plug and stat than two heat range or what :?:

Colder plugs have nothing to do with your thermostat. You should be 1 heatrange colder with a 3.4" pulley. Gap at .055".

The more boost the cooler the plug.
In your case 1 heat range cooler would do. Autolite 605'* and a 180* stat.

What about the NGK iridium plugs

If memory serves, the Irridiums should only be used on the L36... I don't remember why, but I do seem to remember some discussion about them not doing well in a boosted situation.

Platinum'* are a no-no in supercharged or turbo applications. Irridium is ok, but not preferred. Once you drop pulley sizes, you'll be replacing plugs more often. The cost of the Irridiums isn't worth it at that point.

Copper plugs dissipate heat better. Copper is best, Irridium is ok, Platinum is NO.

2 heat ranges is fine too.

I run 104'* @ .054 with my setup with no issues. The old set I ran @ .050 for about 25,000 miles and they still looked fine.

Irridiums are specialized in boosted situations, the electrode tip is much smaller decreasing the size of surface are to be heated up by combustion, in turn reducing the amount of detonation, i used to run them in my turbo corrado running 20psi, but, i have a few friends that ran them in theire mildly to heavily modded L67'*, and from what ive heard the irridiums dont run too well in the l67'* for whatever reason, also you cannot gap Irridium plugs it will damage the electrode