diff --git a/near/src/config.rs b/near/src/config.rs
index 3077a470023..8a2943b8cf4 100644
--- a/near/src/config.rs
+++ b/near/src/config.rs
@@ -60,8 +60,8 @@ pub const EXPECTED_EPOCH_LENGTH: BlockIndex = (5 * 60) / MIN_BLOCK_PRODUCTION_DE
 pub const VALIDATOR_KICKOUT_THRESHOLD: f64 = 0.9;
 
 /// Fast mode constants for testing/developing.
-pub const FAST_MIN_BLOCK_PRODUCTION_DELAY: u64 = 10;
-pub const FAST_MAX_BLOCK_PRODUCTION_DELAY: u64 = 100;
+pub const FAST_MIN_BLOCK_PRODUCTION_DELAY: u64 = 100;
+pub const FAST_MAX_BLOCK_PRODUCTION_DELAY: u64 = 500;
 pub const FAST_EPOCH_LENGTH: u64 = 60;
 
 /// Number of blocks for which a given transaction is valid