When picking out oil for the break in, go with the brand you like but add a can of GM break in lube, you can get it at any dealer.
You could also use Rottela oil for diesel engines, it still has the addatives for proper break in. Sometime in 2004 the oil makers took out the addatives due to emissions on newer cars. They found with out them the converters didn't plug up and they run far cleaner, the draw back is, older engines need the addatives for long life.
I found this out after we replaced a cam in a Pontiac that had only a few thousand miles on it. Two of the lobes were worn smooth. The cam makers are aware of the problem and are working on ways to get the message out. Talk with you dealer!
As far as you cam gear goes, leave it on the new old cam and buy a second set for the new new cam. For $35 you get both gears, and with a small puller you can get the crank gear off with to much trouble. You can also buy the cam retainer plate and spacer from GM or aftermarket for $4 to $5 dallors. I just paid theses prices this week her in Kansas City.
I replaced the harmonic balancer on my 250 at the same time. The rebuilder said to heat it to 250 -275 degrees and it would slip on. That was pretty close to the truth. It went 75% of the way on, the last bit took very little hammer work. I used the old timing gear off the crank to hit against the balancer, don't get out on the edge or the outer ring. Only hit in the very center at the crank!
Somemore advice, check the timing marks of the balancer, mine was rebuilt and the mark is 6 degrees off! Make or borrow a piston stop, something that screws into the spark plug hole that will hit the piston. Use only hand power to turn the engine from one extreme to the other. The timing mark should be dead center. I used masking tape on the balancer and marked zero at each point the piston hit the stop, then took a ruler and found center of the marks. Using a hack saw blade, I simply cut a new timing mark for "zero".
Joe
