diff --git a/marker/v2/converters/pdf.py b/marker/v2/converters/pdf.py
index cf4fbbfa..48741385 100644
--- a/marker/v2/converters/pdf.py
+++ b/marker/v2/converters/pdf.py
@@ -1,30 +1,39 @@
+from marker.v2.providers.pdf import PdfProvider
 import os
+
 os.environ["TOKENIZERS_PARALLELISM"] = "false" # disables a tokenizers warning
 
-from marker.v2.processors.sectionheader import SectionHeaderProcessor
-from marker.v2.providers.pdf import PdfProvider
 import tempfile
-from typing import List, Optional
+from collections import defaultdict
+from typing import Dict, Type
 
 import click
 import datasets
-from pydantic import BaseModel
 
 from marker.v2.builders.document import DocumentBuilder
 from marker.v2.builders.layout import LayoutBuilder
 from marker.v2.builders.ocr import OcrBuilder
 from marker.v2.builders.structure import StructureBuilder
 from marker.v2.converters import BaseConverter
+from marker.v2.models import setup_detection_model, setup_layout_model, \
+    setup_recognition_model, setup_table_rec_model, setup_texify_model
 from marker.v2.processors.equation import EquationProcessor
+from marker.v2.processors.sectionheader import SectionHeaderProcessor
 from marker.v2.processors.table import TableProcessor
-from marker.v2.models import setup_layout_model, setup_texify_model, setup_recognition_model, setup_table_rec_model, \
-    setup_detection_model
 from marker.v2.renderers.markdown import MarkdownRenderer
+from marker.v2.schema import BlockTypes
+from marker.v2.schema.blocks import Block
+from marker.v2.schema.registry import BLOCK_REGISTRY
 
 
 class PdfConverter(BaseConverter):
+    override_map: Dict[BlockTypes, Type[Block]] = defaultdict()
+
     def __init__(self, config=None):
         super().__init__(config)
+        
+        for block_type, override_block_type in self.override_map.items():
+            BLOCK_REGISTRY[block_type] = override_block_type
 
         self.layout_model = setup_layout_model()
         self.texify_model = setup_texify_model()
diff --git a/poetry.lock b/poetry.lock
index e4e8dfcb..c4c900ca 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1716,6 +1716,21 @@ profiling = ["gprof2dot"]
 rtd = ["jupyter_sphinx", "mdit-py-plugins", "myst-parser", "pyyaml", "sphinx", "sphinx-copybutton", "sphinx-design", "sphinx_book_theme"]
 testing = ["coverage", "pytest", "pytest-cov", "pytest-regressions"]
 
+[[package]]
+name = "markdownify"
+version = "0.13.1"
+description = "Convert HTML to markdown."
+optional = false
+python-versions = "*"
+files = [
+    {file = "markdownify-0.13.1-py3-none-any.whl", hash = "sha256:1d181d43d20902bcc69d7be85b5316ed174d0dda72ff56e14ae4c95a4a407d22"},
+    {file = "markdownify-0.13.1.tar.gz", hash = "sha256:ab257f9e6bd4075118828a28c9d02f8a4bfeb7421f558834aa79b2dfeb32a098"},
+]
+
+[package.dependencies]
+beautifulsoup4 = ">=4.9,<5"
+six = ">=1.15,<2"
+
 [[package]]
 name = "markupsafe"
 version = "3.0.2"
@@ -5208,4 +5223,4 @@ propcache = ">=0.2.0"
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.10"
-content-hash = "87f2bf6e84db6c7100db24777a4104096cb963d9bea7380e520dbc1bd8f2feb7"
+content-hash = "4cb4a1d2f40994498d5657bcb5ab37e7ec9c4bb867015d34131c53000eacfbee"
diff --git a/pyproject.toml b/pyproject.toml
index d2b49103..233e6ecd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,6 +38,7 @@ filetype = "^1.2.0"
 regex = "^2024.4.28"
 pdftext = "^0.3.18"
 tabled-pdf = { git = "https://github.com/VikParuchuri/tabled.git", branch = "dev-mose/compilation-updates" }
+markdownify = "^0.13.1"
 
 [tool.poetry.group.dev.dependencies]
 jupyter = "^1.0.0"
diff --git a/tests/conftest.py b/tests/conftest.py
index 178470a6..2c63a934 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -3,13 +3,17 @@
 
 import datasets
 import pytest
+from typing import Dict, Type
 
+from marker.v2.schema import BlockTypes
+from marker.v2.schema.blocks import Block
 from marker.v2.models import setup_layout_model, setup_texify_model, setup_recognition_model, setup_table_rec_model, \
     setup_detection_model
 from marker.v2.builders.document import DocumentBuilder
 from marker.v2.builders.layout import LayoutBuilder
 from marker.v2.builders.ocr import OcrBuilder
 from marker.v2.schema.document import Document
+from marker.v2.schema.registry import BLOCK_REGISTRY
 
 
 @pytest.fixture(scope="session")
@@ -48,13 +52,22 @@ def table_rec_model():
 
 
 @pytest.fixture(scope="function")
-def pdf_provider(request):
+def config(request):
+    config_mark = request.node.get_closest_marker("config")
+    config = config_mark.args[0] if config_mark else {}
+
+    override_map: Dict[BlockTypes, Type[Block]] = config.get("override_map", {})
+    for block_type, override_block_type in override_map.items():
+        BLOCK_REGISTRY[block_type] = override_block_type
+
+    return config
+
+
+@pytest.fixture(scope="function")
+def pdf_provider(request, config):
     filename_mark = request.node.get_closest_marker("filename")
     filename = filename_mark.args[0] if filename_mark else "adversarial.pdf"
 
-    config_mark = request.node.get_closest_marker("config")
-    config = config_mark.args[0] if config_mark else None
-
     dataset = datasets.load_dataset("datalab-to/pdfs", split="train")
     idx = dataset['filename'].index(filename)
 
@@ -65,10 +78,7 @@ def pdf_provider(request):
 
 
 @pytest.fixture(scope="function")
-def pdf_document(request, pdf_provider, layout_model, recognition_model, detection_model) -> Document:
-    config_mark = request.node.get_closest_marker("config")
-    config = config_mark.args[0] if config_mark else None
-
+def pdf_document(request, config, pdf_provider, layout_model, recognition_model, detection_model) -> Document:
     layout_builder = LayoutBuilder(layout_model, config)
     ocr_builder = OcrBuilder(detection_model, recognition_model, config)
     builder = DocumentBuilder(config)
diff --git a/tests/test_overriding.py b/tests/test_overriding.py
new file mode 100644
index 00000000..b70bb1c7
--- /dev/null
+++ b/tests/test_overriding.py
@@ -0,0 +1,18 @@
+import pytest
+
+from marker.v2.schema import BlockTypes
+from marker.v2.schema.document import Document
+from marker.v2.schema.blocks import SectionHeader
+
+
+class NewSectionHeader(SectionHeader):
+    pass
+
+
+@pytest.mark.config({
+    "page_range": [0],
+    "override_map": {BlockTypes.SectionHeader: NewSectionHeader}
+})
+def test_overriding(pdf_document: Document):
+    assert pdf_document.pages[0]\
+        .get_block(pdf_document.pages[0].structure[0]).__class__ == NewSectionHeader