Hi re building and pretty much going off of the geocities z car garage http://datsunzgarage.com/ and it says that main bearings should be factory, but called the dealer and they want 140$... said there were only 15 sets in the US, what would be a good substitute to factory? Also what happened to that Z show @ summit in ohio, last year I missed it by an hour because I couldn't figure out when it was this year I havent seen anything.

I used Clevite 77 mains. Ten years ago, no problems. MS1106P is the part number. I believe I got mine through Napa. IIRC they were about $32. Even today, they'd be much less than $140

I've used Clevite 77 bearings in many engines builds (of all types). The tri-layer construction is great and they hold up to a lot of abuse. These will be going into my L6 stroker engine too.