Chasing the threads is easy. Just do it when you've got some energy and patience left.
What you want is an "Intermediate" or "taper" type. I'll dig up the size when I have a moment. The only real trick is keeping the tap VERY well lubed and cleaning out the hole frequently (especially important with a block that hasn't had the threads chased in a long time). So, you take head off and clean out the bolt hole thoroughly, lube the tap with some lightweight motor oil, start threading the tap in (getting it started is the tricky part, DO NOT LET IT MISTHREAD!!!!!!!!!!!), then slowly and steadily thread the tap in half way or so. Now remove and clean the tap and finish threading it into the bolt hole. Remove the tap, clean it and the hole out thoroughly and thread the tap back into the hole and chase it the whole way to be sure everything is smooth. Remove the tap, clean out the hole and tap again and move on to the next.
When I say the manufacturer's specs I meant the manufacturer of the fastener... not the car. ARP specifies 75ft lbs for 7M head bolts and 90ft lbs for 7M head studs.
By the way, there is actually a difference between a "chase" and a "tap". A chase is generally a little undersized and doesn't cut the block material as much. These are intended to correct misshapen threads. Taps are intended for cutting new threads into a material. The difference with a cast iron block isn't a critical one, although I think with an aluminum block a tap in place of a chase would be a big no-no.