I run the stock oil pump and I'm pushing nearly 600 rwhp. Not sure on the need to swap harmonic balancers.
+1... I could have purchased a forged and balanced short block for what I paid for the new guts and labor to tear mine open.In this day and age it’s completely insane to put your own shortblock together when taking into account how inexpensive it is to just order one up. The price difference between the parts and machining and a built shortblock is so small it’s not worth the time, effort, aggravation, potential problems, need for specialty tools, etc. I can build motors in my sleep and there is no way I would put my own shortblock together. I am much better off spending that time doing what I do for a living and getting paid for it.