diff --git a/protocol-testing/Cargo.lock b/protocol-testing/Cargo.lock
index 343020e..be60f27 100644
--- a/protocol-testing/Cargo.lock
+++ b/protocol-testing/Cargo.lock
@@ -2720,6 +2720,7 @@ dependencies = [
  "postgres",
  "serde",
  "serde_json",
+ "serde_yaml",
  "tokio",
  "tracing",
  "tracing-subscriber",
diff --git a/protocol-testing/Cargo.toml b/protocol-testing/Cargo.toml
index c5fb3d9..bd76d81 100644
--- a/protocol-testing/Cargo.toml
+++ b/protocol-testing/Cargo.toml
@@ -19,3 +19,4 @@ serde = { version = "1.0.218", features = ["derive"] }
 hex = "0.4.3"
 tracing-subscriber = "0.3.19"
 postgres = "0.19.10"
+serde_yaml = "0.9.34"
diff --git a/protocol-testing/src/config.rs b/protocol-testing/src/config.rs
index 2580f3d..2ebdff4 100644
--- a/protocol-testing/src/config.rs
+++ b/protocol-testing/src/config.rs
@@ -1,6 +1,5 @@
 use std::collections::HashMap;
 
-use figment::providers::Format;
 use hex::FromHex;
 use serde::{Deserialize, Serialize};
 
@@ -18,9 +17,9 @@ impl From<String> for HexBytes {
     }
 }
 
-impl Into<String> for HexBytes {
-    fn into(self) -> String {
-        format!("0x{}", hex::encode(self.0))
+impl From<HexBytes> for String {
+    fn from(val: HexBytes) -> Self {
+        format!("0x{}", hex::encode(val.0))
     }
 }
 
diff --git a/protocol-testing/src/utils.rs b/protocol-testing/src/utils.rs
new file mode 100644
index 0000000..6175473
--- /dev/null
+++ b/protocol-testing/src/utils.rs
@@ -0,0 +1,134 @@
+use std::{error::Error, fs, path::Path, process::Command};
+
+use figment::{
+    providers::{Format, Yaml},
+    value::Value,
+    Figment,
+};
+
+/// Build a Substreams package with modifications to the YAML file.
+pub fn build_spkg<F>(yaml_file_path: &str, modify_func: F) -> Result<String, Box<dyn Error>>
+where
+    F: FnOnce(&mut Value) -> Result<(), Box<dyn Error>>,
+{
+    // Create a backup file of the unmodified Substreams protocol YAML config file.
+    let backup_file_path = format!("{}.backup", yaml_file_path);
+    fs::copy(yaml_file_path, &backup_file_path)?;
+
+    let figment = Figment::new().merge(Yaml::file(yaml_file_path));
+    let mut data: Value = figment.extract()?;
+
+    // Apply the modification function to update the YAML files
+    modify_func(&mut data).expect("Failed to modify the YAML config file.");
+
+    let parent_dir = Path::new(yaml_file_path)
+        .parent()
+        .unwrap_or_else(|| Path::new(""))
+        .to_str()
+        .unwrap_or("");
+
+    let package_name = data
+        .clone()
+        .find("package")
+        .expect("Package not found on YAML")
+        .find("name")
+        .expect("Name not found on YAML")
+        .as_str()
+        .expect("Failed to convert name to string.")
+        .replace("_", "-");
+
+    let binding = data
+        .clone()
+        .find("package")
+        .expect("Package not found on YAML")
+        .find("version")
+        .expect("Version not found on YAML");
+
+    let package_version = binding.as_str().unwrap_or("");
+
+    let spkg_name = format!("{}/{}-{}.spkg", parent_dir, package_name, package_version);
+
+    // Write the modified YAML back to the file
+    let yaml_string = serde_yaml::to_string(&data)?;
+    fs::write(yaml_file_path, yaml_string)?;
+
+    // Run the substreams pack command to create the spkg
+    match Command::new("substreams")
+        .arg("pack")
+        .arg(yaml_file_path)
+        .output()
+    {
+        Ok(output) => {
+            if !output.status.success() {
+                println!(
+                    "Substreams pack command failed: {}",
+                    String::from_utf8_lossy(&output.stderr)
+                );
+            }
+        }
+        Err(e) => {
+            println!("Error running substreams pack command: {}", e);
+        }
+    }
+
+    // Restore the original YAML from backup
+    fs::copy(&backup_file_path, yaml_file_path)?;
+    fs::remove_file(&backup_file_path)?;
+
+    Ok(spkg_name)
+}
+
+/// Update the initial block for all modules in the configuration data.
+pub fn modify_initial_block(data: &mut Value, start_block: usize) {
+    if let Value::Dict(_, ref mut dict) = data {
+        if let Some(Value::Array(_, modules)) = dict.get_mut("modules") {
+            for module in modules.iter_mut() {
+                if let Value::Dict(_, ref mut module_dict) = module {
+                    module_dict.insert("initialBlock".to_string(), Value::from(start_block));
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use figment::value::Value;
+
+    use super::*;
+
+    fn create_test_data() -> Value {
+        let file_path = Path::new("src/assets/substreams_example.yaml");
+        let figment = Figment::new().merge(Yaml::file(file_path));
+
+        figment
+            .extract()
+            .expect("Failed to parse YAML file")
+    }
+
+    #[test]
+    fn test_modify_initial_block_normal_case() {
+        let mut data = create_test_data();
+
+        // Apply modification
+        let new_block = 12345;
+        modify_initial_block(&mut data, new_block);
+
+        // Verify all modules now have the correct initialBlock
+        if let Value::Dict(_, dict) = &data {
+            if let Some(Value::Array(_, modules)) = dict.get("modules") {
+                for module in modules {
+                    if let Value::Dict(_, module_dict) = module {
+                        if let Some(Value::Num(_, block)) = module_dict.get("initialBlock") {
+                            assert_eq!(block.to_u128().unwrap(), new_block as u128);
+                        } else {
+                            panic!("initialBlock not found or has wrong type");
+                        }
+                    }
+                }
+            } else {
+                panic!("modules not found or has wrong type");
+            }
+        }
+    }
+}