Where to drill hole in fire wall for after market gauges?

[That_91K1500]

Installing a small after market water temp and oil pressure gauge in my 88 c1500 Silverado. Just wanting suggestions for where to drill the holes to get the lines through and too the engine bay haven’t been able to find any photos or videos about it.(picture shows where I would like to mount the gauges)

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[Nad_Yvalhosert]

Find the indent/perforation for the clutch master (hoping you have an automatic tranny). That's a perfect place with a known cavity. One where you won't drill through a wiring harness or fuel line, etc. Line the hole with a Grommet to prevent wire chafing too.
Additionally, there's a power distribution node right next to said area to pick up backlight power for the gauge.

 

[That_91K1500]

Find the indent/perforation for the clutch master (hoping you have an automatic tranny). That's a perfect place with a known cavity. One where you won't drill through a wiring harness or fuel line, etc. Line the hole with a Grommet to prevent wire chafing too.
Additionally, there's a power distribution node right next to said area to pick up backlight power for the gauge.

Awesome thanks for the info

 

[That_91K1500]

Is this circular indent what your referring too?

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[Nad_Yvalhosert]

Yes. Not the spot welds, but the 1.5"-ish diameter circle right next to the vacuum booster almost dead center in your picture.