I too just replaced the water pump on my '93 Brave with 454. I didn't remove the radiator because I did all the work from the top of the motor inside the coach. Initially took over three hours to replace, then filled radiator with water, started the motor and noticed a leak. Gasket move

. Started from square one, replaced gaskets, re-assembled components...done in 30 minutes. BTW while at it, I replaced all the belts and both radiator hoses.
One thing for anyone doing this yourself, bring your existing water pump with you to the parts house because the replacement year for mine was from a '73-'84 GMC that had an extra threaded "boss" that the '93 year model didn't.