On mine, I'm not using the rear bolt since I ran out of patience trying to put it and used a decent amount of RTV on the gasket (all of it). So far it's not leaking (been about six mths). Also, pay close attention to what Keith460 mention about going too deep with the drilling. You'll be amazed how easy is to break into the coolant passages. It happened to me, but after realizing that it was not the end of the world, I just used thread sealant on the driver's side bolts and Voila!!! No leaks. It definitely worth the effort, changes the look of the engine from miles away. Remember to cut off the studs on the valve rockers bridges!!!!!
TropicalNusselt- 1986 CJ7 w/ 258, T5, D300, D30/D44(3.31:1), Weber 38DGES, DUI, 2.5" Lift, 33" X 12.5" X 16", DC1