Some general observations about the new F1B engine vs the Apollo era F-1 engine.
1. Ditching the Turbo pump after flow injection makes for a simpler engine but it also shows to much academia not enough intuition. Those Apollo guys made a big deal of turbo pump through flow injection to the primary chamber for a reason. Anybody who has ever built anything fast can tell you why.
2. Ditching the radial tube arrangement due to manufacturing complexity assumes you were going to manufacture a radially arrayed tube structure the same way the Apollo engineers did. This does not have to be the case. It is a brilliant design that gets the maximum flow for the minimum mass. Do the simple math for the tube area vs a double chamber layer design + supporting internal baffles. It is good to note the Redstone engines and the V2 were all part of a long history of double wall design. They abandoned it for a REASON. I can think of at least 3 different ways to manufacture that original Apollo chamber design that are economical and low in manual assembly / labor.
3. Your still building your grand parents rocket engine. While I understand that aerospace is typically conservative WTF for. We are so far beyond this standard rocket combination and we need to move on. The next generation of engines will clearly be hybrid rocket jet compounds with some ambient air breathing facility and this engine isn’t it …..
4. After a bit of study it is really quite exciting to realize that you don’t need to be either JPL or a large research institute to build a decent engine any more. All you need is to be half competent prepared to acknowledge the reality of risk and to push the boundaries.