Thanks Tim. Anecdotal is better than nothing. I have 44s in my 261 but that was more because the vendor sent me what I ordered, which was plugs for a 261. How does todays fuels play into this, or things that GM didnt consider when writing the manual? What did they learn from it for later years? I havent researched what the 56, 57, 58, 59, 60, 61, 62 truck manuals suggest. I am just too busy these days to do alot of research. I am not being argumentative. Just curious. Thanks!
