Dusty, I have used heli-coils on a lot of different threaded holes. The process is fairly simple, and can be done with a hand drill if that is all you have (a mag-base drill is better). The cast iron is fairly easy to drill. The biggest caution is to do a good job drilling the hole - get it centered correctly and drill straight, and use a cutting fluid like TapMagic. When you tap the hole with the tap provided in the Heli-Coil set, use the Tap Magic, and back up a couple of turns of the tap every so often. Go slow with the tap, these can break and are a bear to get out of a hole once broken. You can turn the tap with an adjustable wrench, but getting a cheap tap handle or using a 8-point socket on a T-handle type bar would give you better control. Starting the tap is critical - make sure the tap is going in as straight as possible, and go slow until you have made a couple of rounds.
There are different length Heli-Coils, so determine which length you need prior to purchasing.
Is the engine out of the car? The process will be much simpler if it is, but you should be able to do it even with the engine in the car. The hole closest to the firewall might be tough tho.........I can't remember how much room there is at the back end of the block.
