Should I go to a colder set of plugs right away? I am planning on doing a 3.4" pulley swap very soon. Can i run a colder set of plugs on a stock engine without much problem?

Sure. You'll be fine. Just make sure you get your gaps right. NGK TR55'* are one step colder, and should be gapped at .055".

Thanks, do you by chance know which autolite plugs to use? I have more acess to them (Walmart )

Try the NGK tech talk article in Techinfo. I think there'* an autolite reference in that.

I use Autolite 104'* so far. I only have about 100 miles on them though.
I drove about 50 miles with a stock engine, Did my mods and have driven about 50 since.
They looked fine at last check. Several members here mentioned the 104'* were too cold however.
The article Will mentions 104'* and 605'* I think.

JLathem

605'* are 1 heat range colder than stock
104'* are 2 heat ranges colder
103'* are 3 heat ranges colder

Those are all autolite numbers. Not sure about any colder, as you would have a crazy car, and should know by then