“Gal reminds me of the highway between Fort Worth and Dallas. No curves” is a saying by the cartoon rooster Foghorn J. Leghorn in the 1953 cartoon Of Rice and Hen. Foghorn Leghorn spoke with a strong Southern accent, but not necessarily a Texas accent.
   
There are several highways between Fort Worth and Dallas (see the Wikipedia entry below) and some do have curves.
   
     
Wikipedia: Foghorn Leghorn and The Barnyard Dawg
Foghorn Leghorn (full name Foghorn J. Leghorn, according to 1950s comics produced by studio staffers) is a large, anthropomorphic adult rooster with a strong Southern accent and a penchant for mischief. He first appeared in 1946 in a Henery Hawk film entitled Walky Talky Hawky. All of the motion picture Foghorn Leghorn cartoons were directed by Robert McKimson, and the rooster vies with the Tasmanian Devil as the most popular character associated with the director.
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Foghorn’s voice was created by Mel Blanc and was later performed by Joe Alaskey, Billy Farmer, Greg Burson and Jeff Glen Bennett. It was patterned after the character of Senator Claghorn, a blustering Southern politician who was a regular character on the Fred Allen radio show. Senator Claghorn was created and voiced by radio comedian Kenny Delmar and later voiced by Jeff Glen Bennett. Foghorn Leghorn used a number of Claghorn’s catch phrases, like “That’s a joke… I say, that’s a joke, son.” The references to Claghorn were obvious to much of the audience when the Foghorn Leghorn cartoons first premiered, but like many of the references in WB cartoons of the era, they have since become dated. A toddler version of Foghorn made an appearance in Baby Looney Tunes.
 
A leghorn is a breed of chicken, and foghorn describes the character’s loud, overbearing voice. At its most raucous, it sounds similar to that of Blanc’s Yosemite Sam. Both parts of the name also suggest the association with “Senator Claghorn.”
     
Internet Movie Database
Memorable quotes for
Of Rice and Hen (1953)
Foghorn Leghorn: Gal reminds me of the highway between Fort Worth and Dallas. No curves. 
 
Wikipedia: List of Dallas-Fort Worth area freeways
The following is a list of the freeways and tollways in the Dallas/Fort Worth, Texas area:...
   
Google Groups: rec.arts.animation
Newsgroups: rec.arts.animation
From: .(JavaScript must be enabled to view this email address) (Ralph Capasso)
Date: 29 Aug 90 15:00:29 GMT
Local: Wed, Aug 29 1990 10:00 am
Subject: Re: Quotes2
 
Just thought I’d throw in my $.02 (and my personal fav FogHorn quotes):
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...and my all-time favorite Foggie:
“That girl reminds me of the highway between Ft.Worth and Dallas—no curves.”
 
grupthink
Favorite Foghorn Leghorn Quote/Saying
Started on January 22, 2007
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5. That girl’s like that road between Fort Worth and Dallas,
No Curves!