1/8 NPT Female to 1/4 BSP BSPT Male Oil Pressure Gauge Sensor Adapter Fitting, i think this is what your gonna need.I just ordered the dual unit.
If anyone knows the thread/pitch info I'd appreciate it. I'll report back when it's all installed. Fingers crossed.
I decided to give this a try over the Longacre unit because of the dual sensors. I will still use the Speedhut temp gauge to monitor coolant temp and this things will be used only for the alarm functions.

1/8 NPT Female to 1/4 BSP BSPT Male Oil Pressure Gauge Sensor Adapter Fitting | eBay
Male : 1/4 BSP / BSPT. MAMBA Brass Adapter Fitting Bushing 1/4 BSP Male to 1/8 NPT Female (Oil Pressure Gauge). Female: 1/8 NPT. Width: 16mm. Length: 17mm. Product Situation.
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