I would like to know where the best place to penetrate the firewall is, say, for installing aftermarket lighting (and having a cabin switch) or pulling circuits directly from the battery into the cabin. Holes should not ever be any bigger than a quarter inch.

do you have a vulcan or a duratec?

if you have a vulcan then just use the factory grommet, its located above the throttle cable grommet.

if you have a duratec, good luck finding a place where you can get to it on the backside, i just ran mine through the fender-A pillar gap and into the cabin there.

Thanks, I think I got the Vulcan engine, it's the "little" 3 liter V6. It tells for sure in my manual, but it's the smallest of the three. Dunno, it may be a generic, a Vulcan, and the SHO if I remember correctly now. There were three.

ya, if its the lowest output one then you have a vulcan.

True. After looking at the manual again, the smallest is the 3 liter Vulcan, then the 3.6 liter Duratec (I think variants of this are still used on the F150's and rangers!), and then the post-4 liter SHO's the big one.

the Duratec is also 3.0L like the vulcan. it is not used in any trucks, but it is used in the FiveHundred, Escape, Freestyle, Mazda 6S, Lincoln LS V6, and Jaguar X-Type and S-type 3.0's.

The SHO V8 is 3.4L

The vulcan is also available in the Ranger and used to be the base engine in early Aerostars and a few early windstars, it was also an engine for the first gen Probe LX and was optional on the '92-'94 Tempo and Topaz.