1,4xx miles in 26 hours many years ago,in a 1972 Olds 98,from Dallas,Tx/ Whittier,Ca. 
(a suburb east of L.A.)It took LOTS of coffee & cokes!!...and a few stops for Gas & Food & Rest Stops? Also did Dallas/Phoenix once in my '95 Crown Vic in about 16 hrs,(Edit: I keep gas/mileage records.I looked it back up.15 hr,37 min.)(about 1,000-1,100 mi,all Interstates)and my very best(or worst,depending on outlook??) was Dallas,Tx to just outside of Louisville,Ky(not sure of miles..700 or so? And rain half the way!!)in 13+ hrs.(Was going to Cincinatti,Oh,Tried going straight thru,but I got too sleepy....I had to pull off...less than 100mi from destination?)Also did Dallas,Tx/Wichita,Ks in 4 hr,45 min(365 mi 
)and New Orleans,La/Dallas,Tx in 8hr,10min(520+ mi)both times were at night,in my '86 Gran Fury.(Note: I went back to edit,seems half of it didn't post,and the smileys were missing.Also corrected the times.)
(a suburb east of L.A.)It took LOTS of coffee & cokes!!...and a few stops for Gas & Food & Rest Stops? Also did Dallas/Phoenix once in my '95 Crown Vic in about 16 hrs,(Edit: I keep gas/mileage records.I looked it back up.15 hr,37 min.)(about 1,000-1,100 mi,all Interstates)and my very best(or worst,depending on outlook??) was Dallas,Tx to just outside of Louisville,Ky(not sure of miles..700 or so? And rain half the way!!)in 13+ hrs.(Was going to Cincinatti,Oh,Tried going straight thru,but I got too sleepy....I had to pull off...less than 100mi from destination?)Also did Dallas,Tx/Wichita,Ks in 4 hr,45 min(365 mi )and New Orleans,La/Dallas,Tx in 8hr,10min(520+ mi)both times were at night,in my '86 Gran Fury.(Note: I went back to edit,seems half of it didn't post,and the smileys were missing.Also corrected the times.)