Yes, the tooling can be used with the engine installed. Just pack some paper towels or rags into the timing cover to prevent shavings from getting into the crankcase. There's no point in having a securely-held harmonic balancer on a crankshaft that's been ruined by metal shavings in the bearings. I have lost two tooling kits by loaning them to forum "members" with very low post counts. They paid the deposit, and just kept the kit. I'll be glad to sell a kit- - - -just say you want to buy one. If you rent it PLEASE return it for a refund of most of the deposit. Any properly-sharpened drill bit and/or tap is adequate. Chevy crankshafts are tough, not hard, and anyone with more than three brain cells to rub together should be able to do a good job of drilling and tapping the crank, as long as you don't get impatient and try to force the tap. Turn it clockwise about 3/4-1 turn with lots of lubricant, then back up 1/4 turn to break off the chips. I like to thread the hole about 1 1/4" deep with a 7/16-20 thread which is the same center bolt that later-model Chevy V8's have. I provide a new, or freshly-sharpened drill bit and a sharp tap with the kit, along with a jackscrew push tool to install the balancer without having to hammer it on.
Forum members with less than five posts are "moderated", meaning they cannot participate in the private message system, either sending or receiving messages that don't appear on the open forum. Once you have a few more posts under your belt, you can access the membership list, which contains my email address, or we can communicate by private message.
I'm looking forward to hearing from you.
Jerry
