I'm finally ready to give in to temptation and drop pulley size.
The zzp charts are a little confusing. The car is a 2004 Impala SS, but they say 3.5 should be stock. Mine is no doubt 3.8.
I'm running Autolite 104 plugs, 180 tstat, 2.5" catless zzp downpipe, and a very basic tune. Have at most .2-.5 of kr under very heavy acceleration.
Can I do a 3.5, or err on the side of caution and go 3.6?