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3.23 or 3.55 behind 71 340 727 Auto??? #781918 08/23/10 09:52 PM 08/23/10 09:52 PM
Joined: Apr 2003 Posts: 915 near New Haven, CT F fireeng OP super stock
fireeng OP super stock F Joined: Apr 2003 Posts: 915 near New Haven, CT	I'm finally getting my car done. I have my choice of ratios as I have one of each in my stcok pile. I'm building the car mild enough so my wife could drive it if she likes. I'm leaning toward the 3.55s so its a little quicker off the liune but I'd also like to drive at 65 mph for 40 miiles or so every once and a while. I've been out of the game since I was a teenager so I could use some knowledge on how these ratios differ. Thanks.... 2016 Diesel Ram 3500 Mason Dump 1971 Challenger 2013 Jeep Wrangler 1979 Dodge Ram Power Wagon 400 Mini Pumper My other car is a Fire Truck.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: fireeng] #781919 08/23/10 10:04 PM 08/23/10 10:04 PM
Joined: Oct 2004 Posts: 480 Kentucky, USA D derekeh mopar
derekeh mopar D Joined: Oct 2004 Posts: 480 Kentucky, USA	I would lean towards 3.23.... but they arent that difficult to swap out. Try both!

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: fireeng] #781920 08/23/10 10:05 PM 08/23/10 10:05 PM
Joined: Jan 2003 Posts: 20,590 Eagle, Idaho Neil The Doctor is in.
Neil The Doctor is in. Joined: Jan 2003 Posts: 20,590 Eagle, Idaho	I like 3:55's on the street, but I wouldn't go with a tire shorter than 26" in the rear if you want to hit the highway for any great distance.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: derekeh] #781921 08/23/10 10:05 PM 08/23/10 10:05 PM
Joined: Apr 2003 Posts: 915 near New Haven, CT F fireeng OP super stock
fireeng OP super stock F Joined: Apr 2003 Posts: 915 near New Haven, CT	I didn't even consider tire size. What size tire is 26" tall? Last edited by fireeng; 08/23/10 10:07 PM. 2016 Diesel Ram 3500 Mason Dump 1971 Challenger 2013 Jeep Wrangler 1979 Dodge Ram Power Wagon 400 Mini Pumper My other car is a Fire Truck.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: derekeh] #781922 08/23/10 10:06 PM 08/23/10 10:06 PM
Joined: Sep 2004 Posts: 6,906 IL, Aurora A ademon master
ademon master A Joined: Sep 2004 Posts: 6,906 IL, Aurora	3.55, especially if going with a tire taller that 26"

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: fireeng] #781923 08/23/10 10:08 PM 08/23/10 10:08 PM
Joined: Jan 2003 Posts: 20,590 Eagle, Idaho Neil The Doctor is in.
Neil The Doctor is in. Joined: Jan 2003 Posts: 20,590 Eagle, Idaho	Quote: I didn't even consider tire size. What size tire is 26" tall? 235-60-15 are advertised as being 26" in diameter.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: Neil] #781924 08/23/10 10:11 PM 08/23/10 10:11 PM
Joined: Apr 2003 Posts: 915 near New Haven, CT F fireeng OP super stock
fireeng OP super stock F Joined: Apr 2003 Posts: 915 near New Haven, CT	235-60-15 are advertised as being 26" in diameter. I think those are in the ball park of what I would use. Do you think the 3.55s will be really winding out for that highway ride? 2016 Diesel Ram 3500 Mason Dump 1971 Challenger 2013 Jeep Wrangler 1979 Dodge Ram Power Wagon 400 Mini Pumper My other car is a Fire Truck.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: fireeng] #781925 08/23/10 10:16 PM 08/23/10 10:16 PM
Joined: Jan 2003 Posts: 1,481 Outside thedriver pro stock
thedriver pro stock Joined: Jan 2003 Posts: 1,481 Outside	http://vexer.com/automotive-tools/speed-rpm-calculator this is a fun tool to help. 1973 challenger Dana. 4 speed. Low deck.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: thedriver] #781926 08/23/10 10:24 PM 08/23/10 10:24 PM
Joined: Apr 2010 Posts: 1,216 Under My Car Mopar_Country pro stock
Mopar_Country pro stock Joined: Apr 2010 Posts: 1,216 Under My Car	Depends on what your doing with the car, if you want a little strip time then 3.55's.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: ademon] #781927 08/23/10 10:27 PM 08/23/10 10:27 PM
Joined: Feb 2005 Posts: 28,312 Cincinnati, Ohio Challenger 1 Too Many Posts
Challenger 1 Too Many Posts Joined: Feb 2005 Posts: 28,312 Cincinnati, Ohio	Quote: 3.55, especially if going with a tire taller that 26" My 440 car with 28" tires has a 3:54 My 340/727 with 26" tire has a 3:55 I think they are perfect for the street and I can tell the difference between 26-28" tires. I drive my 340 car with 26" tires on the highway all the time. It tachs about 5000 rpm at 120 mph with 3:55 and 26" tires. speedo says 135 but the GPS said 120mph at 4900+ rpms

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: Challenger 1] #781928 08/24/10 01:10 AM 08/24/10 01:10 AM
Joined: Apr 2003 Posts: 1,324 Western Pa joewhite440 pro stock
joewhite440 pro stock Joined: Apr 2003 Posts: 1,324 Western Pa	Quote: Quote: 3.55, especially if going with a tire taller that 26" My 440 car with 28" tires has a 3:54 My 340/727 with 26" tire has a 3:55 I think they are perfect for the street and I can tell the difference between 26-28" tires. I drive my 340 car with 26" tires on the highway all the time. It tachs about 5000 rpm at 120 mph with 3:55 and 26" tires. speedo says 135 but the GPS said 120mph at 4900+ rpms Best ratio for street use. That is why they are hard to find used. If you were going to also race the car. I would have said 3:91's and they are even harder to find used. Good luck and glad you are "back in the game" Joe Sr i

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: joewhite440] #781929 08/24/10 02:45 AM 08/24/10 02:45 AM
Joined: Dec 2008 Posts: 2,782 USA J JoesMopar master
JoesMopar master J Joined: Dec 2008 Posts: 2,782 USA	I'm running a 3.55 behind a 440/727 combo on my '69 Charger with 295/50/15 tires. I run about 3200 RPM @ 70mph. The next car I'm doing is going to have a 3.23.....

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: JoesMopar] #781930 08/24/10 11:55 AM 08/24/10 11:55 AM
Joined: Apr 2003 Posts: 915 near New Haven, CT F fireeng OP super stock
fireeng OP super stock F Joined: Apr 2003 Posts: 915 near New Haven, CT	Thanks for the input. I am going to try the 3.55s and see how it goes. 2016 Diesel Ram 3500 Mason Dump 1971 Challenger 2013 Jeep Wrangler 1979 Dodge Ram Power Wagon 400 Mini Pumper My other car is a Fire Truck.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: fireeng] #781931 08/24/10 07:51 PM 08/24/10 07:51 PM
Joined: Jan 2003 Posts: 300 Mass 6 68bb super street
68bb super street 6 Joined: Jan 2003 Posts: 300 Mass	I put the 3.55's in my 70 dart 318 4 speed over the winter and am very pleased.Doesn't feel at all bad on the highway at 65 - 70. Had 3.23's in my 68, but I like these better.

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: 68bb] #781932 08/25/10 10:39 PM 08/25/10 10:39 PM
Joined: Jan 2003 Posts: 5,791 Hamilton, Ontario Canada Magnum master
Magnum master Joined: Jan 2003 Posts: 5,791 Hamilton, Ontario Canada	Have you considered an overdrive? Any choice you make will always be a compromise. A highway gear is high 2's and a drag gear is 4 something. If it's a restoration or if you don't mind spinning the engine high or enjoy driving in the right lane with everything passing you, disregard. 69 Super Bee, 93 Mustang LX, 04 Allure Super

Re: 3.23 or 3.55 behind 71 340 727 Auto??? [Re: fireeng] #781933 08/25/10 10:48 PM 08/25/10 10:48 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 master
YO7_A66 master Y Joined: Jan 2003 Posts: 5,443 Indiana	I have ran both 3:55/26" tires and 3:91/27" tires and I like them both with my 340/727 Challenger. I don't usually run 70+ (except WOT runs) but up to 70mph cruising speed is fine with either of these combos. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

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