In the answers to the clues below, one letter has been consistently changed to another. Wordplay is fair play. What is the letter switch and what are the corresponding answers?

1. Where to shelve Bibles in the bookstore
2. Careful study of an old record collection
3. Papal indulgences
4. What a meditative ditch digger might get
5. Sounds on a Peter, Paul, and Mary album
6. Doubly disgusting
7. Result of push-cart merchants rushing around
8. Dismaying realization at a bank that's just been robbed

Answers:

The letter switch is F to V:

1. Reverence section 
2. Vinyl analysis
3. Holy waivers
4. Lost in the shovel
5. Trivocals
6. Rank and vile
7. Vendor benders
8. No vault insurance

Credit:
NY Times Crossword
March 9, 2003
Patrick Berry
V - TEN