Firewall Forward Harness Penetrations

[PMD24]

Been thinking about the two holes through the firewall for the wiring harness. The manual maps out the locations but I'm wondering if, for the FF Metal Firewall Forward, it might be cleaner to drill the holes in the overhang so the harness penetrates the firewall vertically. Any feedback would be appreciated.

Also, related to that, should I be waiting until my engine arrives and then tailoring the location of the penetrations to match up with where the engine related terminations are? Engine is a Blueprint 347.

Thanks,

Pat

[Windsorpower]

Been thinking about the two holes through the firewall for the wiring harness. The manual maps out the locations but I'm wondering if, for the FF Metal Firewall Forward, it might be cleaner to drill the holes in the overhang so the harness penetrates the firewall vertically. Any feedback would be appreciated.

Also, related to that, should I be waiting until my engine arrives and then tailoring the location of the penetrations to match up with where the engine related terminations are? Engine is a Blueprint 347.

Thanks,

Pat

I did mine vertically right in the middle. Looks amazing and no issues.

[MaxVmo]

I did mine per the manual, but it became obvious to me after engine install and wiring that you have a lot of space to work with. I didn’t do a heater or wiper motor, so even more space. Keeping a clean install of your dash wiring will also make a big difference.

[kcwitt]

MK IV
Coyote
Firewall forward 2"
Heater in stock location.
Ran all the wiring down, in front of the 2x2 frame.
All the wiring is under the firewall & hidden.
Just enough room left for the fuel regulator & Coyote fuse panel in the engine compartment.
The two recommended holes are in the suggested place but going down not through the firewall.

[Highplainsdakota]

I have the FFmetal forward firewall and had this same question. I elected like many others to drill down. I placed the holes where the main fuse box wiring harness determined the connections to be. Here’s a pic.212517

[JMD]

I drilled my holes vertically into the overhang. So much cleaner looking. IIRC I used three smaller holes instead of two large ones. Just make sure you drill them large enough to pass connectors through and use rubber grommets.