diff --git a/validator/cmd/main.go b/validator/cmd/main.go
index 0e9b270..7c4c492 100644
--- a/validator/cmd/main.go
+++ b/validator/cmd/main.go
@@ -59,6 +59,6 @@ func Main() cliapp.LifecycleAction {
 		beaconClient := service.NewBlobSidecarClient(cfg.BeaconConfig.BeaconURL)
 		blobClient := service.NewBlobSidecarClient(cfg.BlobConfig.BeaconURL)
 
-		return service.NewValidator(l, headerClient, beaconClient, blobClient, closeApp), nil
+		return service.NewValidator(l, headerClient, beaconClient, blobClient, closeApp, cfg.NumBlocks), nil
 	}
 }
diff --git a/validator/flags/config.go b/validator/flags/config.go
index ea6144c..b600f27 100644
--- a/validator/flags/config.go
+++ b/validator/flags/config.go
@@ -13,6 +13,7 @@ type ValidatorConfig struct {
 	LogConfig    oplog.CLIConfig
 	BeaconConfig common.BeaconConfig
 	BlobConfig   common.BeaconConfig
+	NumBlocks    int
 }
 
 func (c ValidatorConfig) Check() error {
@@ -24,6 +25,10 @@ func (c ValidatorConfig) Check() error {
 		return fmt.Errorf("blob config check failed: %w", err)
 	}
 
+	if c.NumBlocks <= 0 {
+		return fmt.Errorf("number of blocks must be greater than 0")
+	}
+
 	return nil
 }
 
@@ -40,5 +45,6 @@ func ReadConfig(cliCtx *cli.Context) ValidatorConfig {
 			BeaconURL:           cliCtx.String(BlobApiClientUrlFlag.Name),
 			BeaconClientTimeout: timeout,
 		},
+		NumBlocks: cliCtx.Int(NumBlocksClientFlag.Name),
 	}
 }
diff --git a/validator/flags/flags.go b/validator/flags/flags.go
index befb67b..5fd4bbc 100644
--- a/validator/flags/flags.go
+++ b/validator/flags/flags.go
@@ -27,11 +27,18 @@ var (
 		Required: true,
 		EnvVars:  opservice.PrefixEnvVar(EnvVarPrefix, "BLOB_API_HTTP"),
 	}
+	NumBlocksClientFlag = &cli.IntFlag{
+		Name:     "num-blocks",
+		Usage:    "The number of blocks to read blob data for",
+		Value:    600,
+		Required: true,
+		EnvVars:  opservice.PrefixEnvVar(EnvVarPrefix, "NUM_BLOCKS"),
+	}
 )
 
 func init() {
 	Flags = append(Flags, oplog.CLIFlags(EnvVarPrefix)...)
-	Flags = append(Flags, BeaconClientTimeoutFlag, L1BeaconClientUrlFlag, BlobApiClientUrlFlag)
+	Flags = append(Flags, BeaconClientTimeoutFlag, L1BeaconClientUrlFlag, BlobApiClientUrlFlag, NumBlocksClientFlag)
 }
 
 // Flags contains the list of configuration options available to the binary.
diff --git a/validator/service/service.go b/validator/service/service.go
index 4137a59..adefc36 100644
--- a/validator/service/service.go
+++ b/validator/service/service.go
@@ -21,8 +21,6 @@ import (
 var ErrAlreadyStopped = errors.New("already stopped")
 
 const (
-	// 5 blocks per minute, 120 minutes
-	twoHoursOfBlocks = 5 * 120
 	// finalized l1 offset
 	finalizedL1Offset = 64
 	// Known log for any validation errors
@@ -31,13 +29,14 @@ const (
 	retryAttempts = 10
 )
 
-func NewValidator(l log.Logger, headerClient client.BeaconBlockHeadersProvider, beaconAPI BlobSidecarClient, blobAPI BlobSidecarClient, app context.CancelCauseFunc) *ValidatorService {
+func NewValidator(l log.Logger, headerClient client.BeaconBlockHeadersProvider, beaconAPI BlobSidecarClient, blobAPI BlobSidecarClient, app context.CancelCauseFunc, numBlocks int) *ValidatorService {
 	return &ValidatorService{
 		log:          l,
 		headerClient: headerClient,
 		beaconAPI:    beaconAPI,
 		blobAPI:      blobAPI,
 		closeApp:     app,
+		numBlocks:    numBlocks,
 	}
 }
 
@@ -48,6 +47,7 @@ type ValidatorService struct {
 	beaconAPI    BlobSidecarClient
 	blobAPI      BlobSidecarClient
 	closeApp     context.CancelCauseFunc
+	numBlocks    int
 }
 
 // Start starts the validator service. This will fetch the current range of blocks to validate and start the validation
@@ -64,7 +64,7 @@ func (a *ValidatorService) Start(ctx context.Context) error {
 	}
 
 	end := header.Data.Header.Message.Slot - finalizedL1Offset
-	start := end - twoHoursOfBlocks
+	start := end - phase0.Slot(a.numBlocks)
 
 	go a.checkBlobs(ctx, start, end)
 
diff --git a/validator/service/service_test.go b/validator/service/service_test.go
index 33de554..1454bf2 100644
--- a/validator/service/service_test.go
+++ b/validator/service/service_test.go
@@ -71,7 +71,9 @@ func setup(t *testing.T) (*ValidatorService, *beacontest.StubBeaconClient, *stub
 		data: make(map[string]response),
 	}
 
-	return NewValidator(l, headerClient, beacon, blob, cancel), headerClient, beacon, blob
+	numBlocks := 600
+
+	return NewValidator(l, headerClient, beacon, blob, cancel, numBlocks), headerClient, beacon, blob
 }
 
 func TestValidatorService_OnFetchError(t *testing.T) {