Getting long tube headers, Stage 2 cam , cai and a tune...2010 is at 47k miles. Should I replace the harmonic balancer as preventative maintenance?
47k miles or km? If it's miles and you've got it in the shop anyway, yes, yes, and yes. Better safe than sorry for long term peace of mind.... In those areas at least... If it's km, not as much of an issue.You might want to consider a new timing chain and oil pump as well if you are concerned about preventative maintenance.
Thanks for all the great info everyone. The Springs, lifters, pushrods etc are being upgraded as well. I don’t anticipate separating the motor from the trans to replace the harmonic balancer because it is on the front of the engine. A stall converter wouldn’t be necessary because it is a manual. I will research the oil pump idea.Yes, yes, and yes!
As an extension, I have to say that if you are replacing the cam, you should be doing the top end as well. I would of course advocate a complete heads and valvetrain swap - but at the very least, you should be looking at doing the lifters, pushrods, and rockers and springs.
Again, I will try to say things in a way that people can understand.
When you change out to an aftermarket camshaft, it is going to change the way that your engine is designed to work. More 'lift' from the larger lobes on the cam means that your lifters and pushrods are going to push higher than they are supposed to, and your valves are going to open further into the cylinder and for a longer duration. Maybe not a big deal, since they are simple devices (sort of - those hydraulic lifters are more complicated than you think), but the extra travel on your rocker arms and on your valve springs are very taxing. Especially when they were never designed to move that far, and they haven't had to for some forty seven thousand miles. Again, perhaps a poor comparison, but I am uh... old-ish... and trying to do the splits when I have never done so in my life is a whole lot of painful. Why would you think that your engine can just suddenly do it with no issues? Trust me. The weakest point WILL break.
I definitely recommend replacing the oil pump while you are in there. Oil is your engine's blood. Make sure it flows. Melling is my recommendation.
This is all in agreement with the above suggestions. If you are going to be separating the engine from the trans, then yes, replace the harmonic balancer - Of course you don't have to, but seriously, if you are there just do it. If you are putting in a cam, you should absolutely change your timing chain - this shouldn't even be a question. It's right there, and it has to come off to put the cam in. Yes, replace it with new. This goes along with any studs or bolts. Replace them with new - they are not expensive, but they are torque-spec'd, and they stretch to hold. Do not re-use them.
As a double-extension to the suggestions here, if you are indeed planning to replace the harmonic balancer, then you should consider a stall converter while you are in there. Opinions will vary on this, but I think that a very streetable range is around 3000-3400rpm. You will want some sticky tires, unless you like to smoke them on command.
Good luck with your project. Do it once, do it right, and enjoy the hell out of it.