If your Miata is going to see track use, we recommend a radiator upgrade (with or without the K series engine swap). And even if it's not going to see the track, most original NA and NB Miata radiators are very old by now, and if the plastic tanks are turning brown, it’s time for a replacement.

Thanks to the fact that the K series is easier to keep cool on track than a Miata BP engine, this Mishimoto radiator is an appropriate addition to your swap. 

Although a fan shroud kit is available from Mishimoto, we recommend running a single stock fan for track cars. 

• Direct fit for the 1990-2005 Miatas (select generation above)
• Mishimoto Lifetime Warranty
• Full aluminum construction including durable, TIG-welded end tanks
• Features a two-row, 1.97" thick, efficient brazed aluminum core
• Increased fluid capacity and optimal heat dissipation
• Ideal replacement for the failure-prone stock radiator
• Perfect for use on the street, track, or autocross course
• Includes 1.3 Bar High-Pressure Radiator Cap, which effectively raises the boiling point of engine coolant, providing a safer and more efficient system
• Includes Magnetic Drain plug to capture any metallic debris in your cooling system