Thanks a lot folks!
I heard a good things about pre-71 340, I thought I would rebuid my 69 to stock see how it perform. But...
I did some research, it seems to me that alot 340er recommend Comp cam XE268 rather than MP Purple P4452782(stock-replcaement cam).
I have non-experience with choosing Cam. So if anyone here knew/or have tried both of those Cam above, please make a decision for me, which Cam is right?