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What Size Are The Sensor Ports On My BluePrint Engine?

One of the most common installation questions we receive is determining the thread size of the ports used for oil pressure senders, coolant temperature sensors, fan switches, gauges, and other accessories.

 Small Block Chevy (SBC)

Oil Pressure Port

Most BluePrint SBC oil pressure ports utilize:

1/4" NPT

The most common oil pressure sender location is near the oil filter mounting pad.

Coolant Temperature Ports

Most coolant temperature sensor locations on SBC intake manifolds utilize:

1/2" NPT

Verify the specific intake manifold being used before purchasing fittings or sensors.

Big Block Chevy (BBC)

Oil Pressure Port

Most BBC applications utilize:

1/4" NPT

Oil pressure ports are typically located above or near the oil filter housing.

Coolant Temperature Ports

Most intake manifold coolant ports utilize:

1/2" NPT

Depending on the intake design, additional ports may also be available for fan switches, EFI sensors, or mechanical gauges.

Small Block Ford (302 / 306 / 347)

Oil Pressure Port

Most Small Block Ford oil pressure sender locations utilize:

1/4" NPT

Coolant Temperature Ports

Most coolant sensor ports utilize:

1/2" NPT

Always verify the sender matches the thread size and gauge manufacturer requirements.

Before Installing Any Sensor

Always verify:

  • Thread size
  • Thread pitch
  • Sender compatibility
  • Gauge manufacturer requirements

Many aftermarket gauges include adapters that may differ from OEM senders.

Frequently Asked Questions

Can I use a brass adapter?

Yes. Brass adapters are commonly used when transitioning between sender thread sizes and engine port sizes.

Can I force a fitting if it seems close?

No.

NPT threads are tapered and using the incorrect fitting can damage the intake manifold, cylinder head, or engine block.

What thread sealant should I use?

Use a quality thread sealant approved for coolant or oil applications. Avoid using excessive sealant that could enter the engine's oiling or cooling system.

Why won't my sender thread into the port?

Most commonly this is caused by:

  • Incorrect thread size
  • BSP vs NPT thread differences
  • Metric sensor being installed into an NPT port
  • Paint or coating in the threads