I've checked with a couple of automobile machine shops and the use of Heli-Coils was not frequent but was used a couple of times on stripped head bolts. I don't know what the long terms reliability is as the shops didn't know. The general consensus was to get another block.
Jim
Yes, a rather popular repair on ALUMINUM blocks, I worked at Cadillac (GM factory trained specifically on the 4100 and other engines produced by General Motors) when the aluminum V-8 was introduced (the Vega V-8, we used to called it) and that was a factory approved repair on the 4100 which eventually called out for Torque-to-Yield bolts to help alleviate the problem(s). Those style bolts were beginning to become the common (in the 80's, on most everything) because of the pulled threads, particularly in aluminum. The design is to do a basic torque, in pattern, a low torque value first, say of 45 ft.lbs., then a re torque of say 60 ft. lbs. then a rotate of say 90 degrees,(or 180 degrees) then a final turn of say 90 degrees, the specs varied between locations of torquing and various applications.
I mention the above because of any added friction that might be produced by using a Heli Coil. If it were good enough for warranty repairs, I would think it would be good enough for a basic 289 also.
Personally, on a standard performance 289 2V, and/or a Show Only car, I would use a Heli Coil rather than hunting down another doner block. If it were a Daily Driver or Performance engine or had higher than normal compression ratio, maybe a cause to pause and consider another block first.
Good luck, but if done correctly, you really should have no problems. I might, with using new head bolts and a "test"(sacrificial) head gasket, install the head on the bare block (if you are intending on rebuilding the engine) and "feel" how this one torques as compared to the other head bolts.
