I used NGK TR6's in my stock 8# setup with no problems. But now I am going to run 10-12# on my 383 with AFR's. Should I stick with the NGK's or go with Auotlite's. I did a search and it seems to be 50/50. Also the 104's are comparable to TR6's or is it the 103's. What would/are you guys running on similiar setups. Thanks....John

 

TR6 is one heat range colder than stock (so is the Autolite 104). Autolite 103 is 2 heat ranges colder and will probably be needed to 10 - 12# of boost.

 

I have been running 104's with 14lbs for a while without problems.