Author Topic: Acceptable gear ratio for a 1970 Cuda cruiser  (Read 3635 times)

Offline soccernut43

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Acceptable gear ratio for a 1970 Cuda cruiser
« on: October 13, 2017 - 07:54:41 AM »
Is the 3:54 gear ratio for a 1970 Cuda with a Dana 60 acceptable for a cruiser? Looking to put it back on the street.  Thanks!!




Offline Beekeeper

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #1 on: October 13, 2017 - 09:26:12 AM »
Unless you have an overdrive transmission, I'd go no more than 3:23. I had 3:55 in my Bee and it was fun around town but really sucked after a while on the highway. So much so that I swapped in a set of 2:76 for highway cruising.

Offline 1 Wild R/T

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #2 on: October 13, 2017 - 10:25:52 AM »
If your running a Dana 3.54 is about as good as it gets....   Try plugging your tire size & gear ratios in to the linked calculator to see what RPM's you'll be turning...

https://www.e-bodies.org/resources/rpm-speed-gear-tire-size-calculator/

JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
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Offline Rolling_Thunder

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #3 on: November 17, 2017 - 08:31:36 PM »
Ford trucks came with a Dana 60 and I believe a 3:33 ratio - but they are an uncommon gear set...    you're looking at 3.54 for the Dana - could get away with it if you add a 28" tall tire - helps drop the rpms a little bit.
2013 Dodge Challenger R/T - 5.7L / 6-speed

1973 Dodge Challenger Rallye - 340 / Auto

1968 Dodge Charger - 6.1L / 6-speed

1964 Dodge Polara - 440 8-71 / 4-speed

Offline kielbasa

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #4 on: February 27, 2018 - 10:44:15 AM »
acceptable is different things to different people...I personally drove my 4.56 geared car a LOT, even interstate cruising between Milwaukee and Chicago....to me, anything 3.91 and lower seems like grandma gearing.....if running an overdrive trans then I wouldn't even dream of anything less than 4.56's....

Offline 4Cruizn

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #5 on: February 27, 2018 - 01:31:28 PM »
I far as I know, in a dana, 3.55 is the lowest you can get.  Rolling Thunder stated something about a 3.33 in a dana?  I am no expert but didn't think that was available . . .

Offline schtick

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #6 on: April 01, 2018 - 08:41:58 PM »
I far as I know, in a dana, 3.55 is the lowest you can get.  Rolling Thunder stated something about a 3.33 in a dana?  I am no expert but didn't think that was available . . .
My car is 440+6 with Dana 3:54. Driven from CT to the Nats in Ohio, every year to Carlisle and Englishtown(RIP) And sometimes raced With Supercar Races and FAST. F70 Polyglas, 12.5 mpg @70 mph. 3200 RPM. Zero problems. Exhaust is Walker Ultra Flo thru TTI 2 1/2" with H-pipe. No drone and can still have a conversation on the highway.

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Offline 1 Wild R/T

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #7 on: April 01, 2018 - 11:25:51 PM »
I far as I know, in a dana, 3.55 is the lowest you can get.  Rolling Thunder stated something about a 3.33 in a dana?  I am no expert but didn't think that was available . . .

Actually the Ford truck gear is 3.31 which was rare back in the day & virtually non-exsistant today... The Mopar Dana gear is 3.54 not 3.55... 3.55 is the 8.75 ratio....
JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
RM21H9E 69 Road Runner Coupe R4 Performance Red, Sold...
5H21C  65 Falcon 2 dr Wagon... Dog Hauler...

Offline Mopar Mitch

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #8 on: April 04, 2018 - 02:35:09 PM »
I've run highway (with my 727 tranny) using 4.30, 3.91, 3.55, 3.21, and a long time ago a 2.76.   For today's more common higher mph (~70-80), I like the 3.23 as in my car now.  a 3.55 brings it up a little, and the question becomes how long time-wise and at what mph are you willing to cruise?  I like a typical 1-2-3 hour cruise at ~3200-3500 rpm max, ~70-75 mph.  I'm planning to eventually run a 2.94 setup (will drop by ~500 rpm at hwy speeds).

Also, hopefully you have some tall diameter tires, such as 275-60-15 in the rear (28" diameter).... that helps a,little and with some good comfort. 
Autocross/road racers go in deeper... and come out harder!

See  MOPAR ACTION MAGAZINE, AUGUST 2006 ISSUE for featured article and details on my autocross T/A.

Offline jimynick

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Re: Acceptable gear ratio for a 1970 Cuda cruiser
« Reply #9 on: April 04, 2018 - 11:28:06 PM »
My Challenger came with a 3:23 and I've had 3:55's and 3:91's all in 4 speed cars and if your plan is to cruise and you want good mileage and engine wear profiles, I'd go with the 3:23's. My Valiant with the 3:91's ran about 3700 rpm at highway speed. It'd pass most anything- but a gas station. Just my  :2cents: