Oops my bad. I didn't pay attention and saw later where you said V-6. I was mainly reading the original post and did not see a reference to a V-6 only a six. Sorry, I will shut up now.
I also have a 1989 Full size Ford Bronco 4x4 and it also has the bottom of the rear tailgate rusted out. I would like information where to buy the fiberglass one? I also cannot get the 4x4 to work (I think it is an electrical problem with the switch). Any help would be appreciated!
I have an '88 full size with the 302. It has better than 274K miles on the clock and no way would I trade it. I also have the leaking rear engine seal, have replaced the radiator, heater core, alternator, A/C system, distributor, tailgate and getting ready to replace the rear glass motor. Door window motors have been replaced several times. We have a TL and an SC300--the Bronco is my go to every driver. When you figure 18 years and 274K miles, the repairs are easily amortized, especially when you do most of the work yourself. Besides, the grand kids love it.
For those folks who actually know what they are doing with their Ford Bronco and accept that Ford trucks of this vintage were prone to a few problem rust spots, let me offer this advice. There are aftermarket manufacturers out there making fiberglass replacements for just about every body panel on the full-size Bronco, including the tailgate, which DID INDEED have drain holes in it, but moisture caught in the gate between the inner and outer sheet metal would allow rust to begin along the bottom seam, which was LOWER than the drain holes. Replace the tailgate and seal the inside of it with a spray-on truck bed liner and the problem will not return. The same is true of the openings for the rear wheels.
The full-size Bronco was indeed available with a six cylinder engine from the mid 80's through the mid 90's. The 300 CID (4.9L) in-line six not only pulled harder at the bottom of the rpm range than her only slightly larger 302 CID (5.0L) V8 counterpart, it also outlived most Ford small-block V8's in these trucks.
I've heard tons of good things about the 300CID straight six... (in early 80's Mustangs, Ford F150's, etc.)