Over the years, the 848 has become the gold standard of 235/261 heads, so when I do engine rebuilds, I know I will be more popular with the purchaser if it has an 848 on it. As Tim mentioned, 75% of all 235 heads are 848 so its not hard to find them. I have four untested 848's and my hope is two of them will be good. I am not holding my breath. My 261 sports an 848 with the extra holes drilled. The first two I gave the engine shop were bad.
