diff --git a/scripts/health_check/health_check_client.py b/scripts/health_check/health_check_client.py
index 4848735bb7..873727b453 100644
--- a/scripts/health_check/health_check_client.py
+++ b/scripts/health_check/health_check_client.py
@@ -20,6 +20,17 @@ from typing import Dict, List, Optional, Tuple
 import httpx
 import yaml
 
+# Default prompt for health checks - exactly 100k characters
+# Generate a repeating pattern to reach exactly 100,000 characters
+_base_text = "This is a health check test prompt for LiteLLM proxy. "
+_repeat_count = (100000 // len(_base_text)) + 1
+_DEFAULT_COMPLETION_PROMPT = (_base_text * _repeat_count)[:100000]
+
+# Default embedding text - also exactly 100k characters
+_embedding_base_text = "This is a test for vectorization. "
+_embedding_repeat_count = (100000 // len(_embedding_base_text)) + 1
+_DEFAULT_EMBEDDING_TEXT = (_embedding_base_text * _embedding_repeat_count)[:100000]
+
 
 class LiteLLMHealthCheckClient:
     """Client for health checking LiteLLM proxy models."""
@@ -29,8 +40,9 @@ class LiteLLMHealthCheckClient:
         base_url: str,
         api_key: str,
         timeout: int = 120,  # Match Go implementation's 120s timeout
-        completion_prompt: str = "Say this is a test",  # Match Go implementation
-        embedding_text: str = "This is a test for vectorization.",  # Match Go implementation
+        completion_prompt: str = _DEFAULT_COMPLETION_PROMPT,  # Default ~100k chars
+        embedding_text: str = _DEFAULT_EMBEDDING_TEXT,  # Default ~100k chars
+        custom_auth_header: Optional[str] = None,
     ):
         """
         Initialize the health check client.
@@ -41,16 +53,34 @@ class LiteLLMHealthCheckClient:
             timeout: Request timeout in seconds (default: 120, matching Go implementation)
             completion_prompt: Test prompt for chat/completion models
             embedding_text: Test text for embedding models
+            custom_auth_header: Optional custom header name for authentication (e.g., "x-ifood-requester-service").
+                If provided, uses this header instead of standard "Authorization" header.
         """
         self.base_url = base_url.rstrip("/")
         self.api_key = api_key
         self.timeout = timeout
         self.completion_prompt = completion_prompt
         self.embedding_text = embedding_text
-        self.headers = {
-            "Authorization": f"Bearer {api_key}",
-            "Content-Type": "application/json",
-        }
+        
+        # Debug: Print prompt/text lengths
+        print(f"DEBUG: Completion prompt length: {len(self.completion_prompt)} characters", file=sys.stderr)
+        print(f"DEBUG: Embedding text length: {len(self.embedding_text)} characters", file=sys.stderr)
+        
+        # Support custom auth header for proxies with custom authentication
+        # Handle both None and empty string
+        if custom_auth_header and custom_auth_header.strip():
+            custom_auth_header = custom_auth_header.strip()
+            self.headers = {
+                custom_auth_header: f"Bearer {api_key}",
+                "Content-Type": "application/json",
+            }
+            print(f"Using custom auth header: {custom_auth_header}", file=sys.stderr)
+        else:
+            self.headers = {
+                "Authorization": f"Bearer {api_key}",
+                "Content-Type": "application/json",
+            }
+            print("Using standard Authorization header", file=sys.stderr)
 
     def load_models_from_yaml(self, yaml_path: str) -> List[Dict]:
         """
@@ -182,6 +212,8 @@ class LiteLLMHealthCheckClient:
 
             if is_embedding:
                 # Test embedding endpoint (matching Go implementation)
+                embedding_text_length = len(self.embedding_text)
+                print(f"DEBUG: Sending embedding text of length {embedding_text_length} chars to model {model_id}", file=sys.stderr)
                 embedding_response = await client.post(
                     f"{self.base_url}/v1/embeddings",
                     headers=self.headers,
@@ -202,6 +234,8 @@ class LiteLLMHealthCheckClient:
                 result["dimensions"] = dimensions
             else:
                 # Test chat completion endpoint (matching Go implementation)
+                prompt_length = len(self.completion_prompt)
+                print(f"DEBUG: Sending prompt of length {prompt_length} chars to model {model_id}", file=sys.stderr)
                 completion_response = await client.post(
                     f"{self.base_url}/v1/chat/completions",
                     headers=self.headers,
@@ -358,6 +392,11 @@ async def main():
     base_url = os.environ.get("LITELLM_BASE_URL", "http://localhost:4000")
     api_key = os.environ.get("LITELLM_API_KEY", "sk-1234")
     yaml_path = os.environ.get("LITELLM_MODELS_YAML")
+    custom_auth_header = os.environ.get("LITELLM_CUSTOM_AUTH_HEADER")  # e.g., "x-ifood-requester-service"
+    
+    # Debug: Print custom auth header value if set
+    if custom_auth_header:
+        print(f"Custom auth header from env: '{custom_auth_header}'", file=sys.stderr)
 
     if not base_url:
         print("Error: LITELLM_BASE_URL environment variable not set", file=sys.stderr)
@@ -369,10 +408,10 @@ async def main():
 
     timeout = int(os.environ.get("LITELLM_TIMEOUT", "120"))  # Match Go's 120s default
     completion_prompt = os.environ.get(
-        "LITELLM_COMPLETION_PROMPT", "Say this is a test"
+        "LITELLM_COMPLETION_PROMPT", _DEFAULT_COMPLETION_PROMPT
     )
     embedding_text = os.environ.get(
-        "LITELLM_EMBEDDING_TEXT", "This is a test for vectorization."
+        "LITELLM_EMBEDDING_TEXT", _DEFAULT_EMBEDDING_TEXT
     )
     json_output = os.environ.get("LITELLM_JSON_OUTPUT", "").lower() == "true"
     # Optional: only health-check these model IDs (comma-separated). E.g.:
@@ -386,6 +425,7 @@ async def main():
         timeout=timeout,
         completion_prompt=completion_prompt,
         embedding_text=embedding_text,
+        custom_auth_header=custom_auth_header,
     )
 
     # Load models from YAML if provided, otherwise fetch from API
diff --git a/scripts/health_check/health_check_client_README.md b/scripts/health_check/health_check_client_README.md
index e3132499e0..41c7ab7c35 100644
--- a/scripts/health_check/health_check_client_README.md
+++ b/scripts/health_check/health_check_client_README.md
@@ -30,6 +30,14 @@ export LITELLM_MODELS_YAML="/path/to/config.yaml"
 python scripts/health_check/health_check_client.py
 ```
 
+**Option 3: Use custom authentication header**
+```bash
+export LITELLM_BASE_URL="https://litellm.example.com"
+export LITELLM_API_KEY="your-api-key"
+export LITELLM_CUSTOM_AUTH_HEADER="x-custom-auth-header"
+python scripts/health_check/health_check_client.py
+```
+
 ### As a Docker Container
 
 1. Build the Docker image:
@@ -47,6 +55,16 @@ docker run --rm \
   litellm/litellm-health-check:latest
 ```
 
+3. Run with custom authentication header:
+
+```bash
+docker run --rm \
+  -e LITELLM_BASE_URL="https://litellm.example.com" \
+  -e LITELLM_API_KEY="your-api-key" \
+  -e LITELLM_CUSTOM_AUTH_HEADER="x-custom-auth-header" \
+  litellm/litellm-health-check:latest
+```
+
 ### Parallel Execution (Stress Testing)
 
 Run multiple health check containers in parallel:
@@ -65,6 +83,30 @@ export LITELLM_API_KEY="your-api-key"
 ./scripts/health_check/run_parallel_health_checks.sh 16
 ```
 
+**With Custom Auth Header:**
+```powershell
+$env:LITELLM_BASE_URL="https://litellm.example.com"
+$env:LITELLM_API_KEY="your-api-key"
+$env:LITELLM_CUSTOM_AUTH_HEADER="x-custom-auth-header"
+.\scripts\health_check\run_parallel_health_checks.ps1 16
+```
+
+**With Custom Docker Image:**
+```powershell
+$env:LITELLM_BASE_URL="https://litellm.example.com"
+$env:LITELLM_API_KEY="your-api-key"
+$env:LITELLM_CUSTOM_AUTH_HEADER="x-custom-auth-header"
+.\scripts\health_check\run_parallel_health_checks.ps1 -NumParallelJobs 16 -ImageName "your-registry/your-image:tag"
+```
+
+**Bash with Custom Image:**
+```bash
+export LITELLM_BASE_URL="https://litellm.example.com"
+export LITELLM_API_KEY="your-api-key"
+export LITELLM_CUSTOM_AUTH_HEADER="x-custom-auth-header"
+./scripts/health_check/run_parallel_health_checks.sh 16 "your-registry/your-image:tag"
+```
+
 
 ## Configuration
 
@@ -73,14 +115,29 @@ export LITELLM_API_KEY="your-api-key"
 - `LITELLM_BASE_URL` (required): Base URL of the LiteLLM proxy
   - Example: `https://litellm.example.com`
 - `LITELLM_API_KEY` (required): API key for authentication
+- `LITELLM_CUSTOM_AUTH_HEADER` (optional): Custom header name for authentication
+  - Use this when your LiteLLM proxy uses a custom authentication header instead of the standard `Authorization` header
+  - Example: `x-custom-auth-header` (the API key will be sent as `Bearer <api_key>` in this header)
 - `LITELLM_MODELS_YAML` (optional): Path to YAML config file with model_list
   - If provided, reads models from YAML instead of fetching from API
   - Example: `/path/to/config.yaml`
 - `LITELLM_TIMEOUT` (optional): Request timeout in seconds (default: 120)
-- `LITELLM_COMPLETION_PROMPT` (optional): Test prompt for chat/completion models (default: "Say this is a test")
-- `LITELLM_EMBEDDING_TEXT` (optional): Test text for embedding models (default: "This is a test for vectorization.")
+- `LITELLM_COMPLETION_PROMPT` (optional): Test prompt for chat/completion models (default: ~100k characters)
+- `LITELLM_EMBEDDING_TEXT` (optional): Test text for embedding models (default: ~100k characters)
 - `LITELLM_JSON_OUTPUT` (optional): Output results as JSON (default: false)
 
+### Parallel Script Parameters
+
+**PowerShell (`run_parallel_health_checks.ps1`):**
+- `-NumParallelJobs` (optional): Number of parallel containers to run (default: 16)
+- `-ImageName` (optional): Docker image to use (default: `litellm/litellm-health-check:latest`)
+- `-ContainerRuntime` (optional): Container runtime to use (default: `docker`)
+
+**Bash (`run_parallel_health_checks.sh`):**
+- `[num_parallel_jobs]` (optional): Number of parallel containers to run (default: 16)
+- `[image_name]` (optional): Docker image to use (default: `litellm/litellm-health-check:latest`)
+- `[container_runtime]` (optional): Container runtime to use (default: `docker`)
+
 ## Output
 
 ### Standard Output (Human-Readable)
@@ -166,7 +223,20 @@ Run multiple health checks in parallel:
 
 **PowerShell:**
 ```powershell
+# Using default image
 .\scripts\health_check\run_parallel_health_checks.ps1 16
+
+# Using custom image
+.\scripts\health_check\run_parallel_health_checks.ps1 -NumParallelJobs 16 -ImageName "your-registry/your-image:tag"
+```
+
+**Bash:**
+```bash
+# Using default image
+./scripts/health_check/run_parallel_health_checks.sh 16
+
+# Using custom image
+./scripts/health_check/run_parallel_health_checks.sh 16 "your-registry/your-image:tag"
 ```
 
 ### 3. CI/CD Integration
diff --git a/scripts/health_check/run_parallel_health_checks.ps1 b/scripts/health_check/run_parallel_health_checks.ps1
index 856e7f20ec..850fc6baab 100644
--- a/scripts/health_check/run_parallel_health_checks.ps1
+++ b/scripts/health_check/run_parallel_health_checks.ps1
@@ -49,6 +49,11 @@ Write-Host "    2. Set LITELLM_BASE_URL to the correct URL (e.g., http://host.do
 Write-Host "    3. On Linux, you may need to use the host IP instead of host.docker.internal" -ForegroundColor Yellow
 Write-Host ""
 
+# Capture environment variables in parent scope for use in parallel block
+$baseUrl = $env:LITELLM_BASE_URL
+$apiKey = $env:LITELLM_API_KEY
+$customAuthHeader = $env:LITELLM_CUSTOM_AUTH_HEADER
+
 # Run parallel health checks
 # This creates an infinite loop that keeps spawning containers
 # Each container tests all models, then exits, and a new one starts
@@ -57,13 +62,20 @@ while ($true) {
     1..$NumParallelJobs | ForEach-Object -Parallel {
         $runtime = $using:ContainerRuntime
         $imageName = $using:ImageName
-        $baseUrl = $env:LITELLM_BASE_URL
-        $apiKey = $env:LITELLM_API_KEY
+        $baseUrl = $using:baseUrl
+        $apiKey = $using:apiKey
+        $customAuthHeader = $using:customAuthHeader
         
-        & $runtime run --rm `
-            -e LITELLM_BASE_URL="$baseUrl" `
-            -e LITELLM_API_KEY="$apiKey" `
-            -e LITELLM_JSON_OUTPUT="true" `
-            $imageName
+        $envVars = @(
+            "-e", "LITELLM_BASE_URL=$baseUrl",
+            "-e", "LITELLM_API_KEY=$apiKey",
+            "-e", "LITELLM_JSON_OUTPUT=true"
+        )
+        
+        if ($customAuthHeader) {
+            $envVars += "-e", "LITELLM_CUSTOM_AUTH_HEADER=$customAuthHeader"
+        }
+        
+        & $runtime run --rm $envVars $imageName
     } -ThrottleLimit $NumParallelJobs
 }
diff --git a/scripts/health_check/run_parallel_health_checks.sh b/scripts/health_check/run_parallel_health_checks.sh
index 9b6c5d9f39..d1913e3fdd 100644
--- a/scripts/health_check/run_parallel_health_checks.sh
+++ b/scripts/health_check/run_parallel_health_checks.sh
@@ -54,11 +54,18 @@ echo ""
 
 # Function to run a single health check container
 run_health_check() {
-    "$CONTAINER_RUNTIME" run --rm \
-        -e LITELLM_BASE_URL="$LITELLM_BASE_URL" \
-        -e LITELLM_API_KEY="$LITELLM_API_KEY" \
-        -e LITELLM_JSON_OUTPUT="true" \
-        "$IMAGE_NAME"
+    local env_vars=(
+        -e "LITELLM_BASE_URL=$LITELLM_BASE_URL"
+        -e "LITELLM_API_KEY=$LITELLM_API_KEY"
+        -e "LITELLM_JSON_OUTPUT=true"
+    )
+    
+    # Pass through custom auth header if set
+    if [ -n "$LITELLM_CUSTOM_AUTH_HEADER" ]; then
+        env_vars+=(-e "LITELLM_CUSTOM_AUTH_HEADER=$LITELLM_CUSTOM_AUTH_HEADER")
+    fi
+    
+    "$CONTAINER_RUNTIME" run --rm "${env_vars[@]}" "$IMAGE_NAME"
 }
 
 # Run parallel health checks