I'm certainly not debating that a 1500w Kats heater will get the engine warmer than the 400w factory heater. My point is that the 617 doesn't need to be 170F or 107F to start, even just 30F is fine, and a significant improvement when it's 0F outside. This isn't an emergency standby generator that needs to go to full load immediately, and the factory block heater has been sized accordingly.

I do agree that cold start to full load in 6 seconds, the closer you can start to operating temp the better for the life of the engine. Would probably want an oil heating blanket, too.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap