I believe it was about 1971-72 When HOTROD had an article explaining and demonstrating how and what to do to a SB400 to significantly upgrade a 400 for excellent power and performance. Since then, I have been a big fan of SB400s and over the years, I have built about 25 400s. So far, all of them are still ticking, including the 5 in my family.
For a Trifive, a healthy built SB400 is just too natural. EVERYTHING that was bolted to a 265 or 283 is an excellent bolt-on fit. And generally, more economical to build.
There is no question, I DO NOT dispute that power from a well built, big cube, BB is nearly impossible to beat.
Here are are 4 of the 5 SB400s in my family.
All of them are built from GM blocks, heads and GM cast cranks.