Last year before the International Meet, I decided to take the water pump off the engine, and check its condition, since it was original to the car. Upon taking it off, I realized that even though it didn't leak, that the impeller at the rear was worn where it attached to the shaft. I had purchased a NOS (new old stock) water pump, and installed it. I drove the car approximately 3000 miles to Flint and back with no problems. Last week when I was removing parts to clean and paint / detail my engine, I noticed that the water pump that I installed last year is showing signs of leaking from the shaft weep hole. I never saw any indication of a leaking pump, and I am leaning toward this being a result of the seal leaking when I installed it last year. The reason that I bring this up, is that everyone should check their water pump prior to taking a trip. You don't want that water pump to fail while you are on the way to a meet, which will delay your arrival. I suggest that you visually look for any signs of leakage, and if you don't see any, great. Then I suggest that you grab the blades of the fan (with the engine off), at 3 & 9 o'clock, and wiggle it back and forth. If it doesn't have any play in it, great, that means that the water pump and fan clutch (if you have one) are in good mechanical condition. If you detect movement, then I suggest that you replace all the defective parts immediately. If the fan clutch should fail on the road, it will slice the radiator and you will be stranded. If you are looking to win the hard luck trophy, then disregard this advise. If you want to have a pleasant trip, this checking will only take you a few minutes, but can save you many dollars and valuable time.
Now this 4.8 is the same basic engine they've had since the 50's and I've changed my share of pumps in the day and never heard of a gasket failure.