Just wondering what everyone is running for a rear end ratio? I will be installing my 302 this Spring with a mild build up, c-4 trans. Current Ratio is 3.00. Trans has the mild Trans-go install. Just what something that will be fun around town, but still can take out expressway. My thought was a 3.55 ratio what do you think? Thanks for input....Kirk Spring and Columbus Ford Show only about 7 weeks away
3.55 seems to be the general consesus. Running 4.11's~tall tire and 60mph shows 3+ grand. I have cruised town with 4.11's (28 inch tire) and anything under 45mph is cool. I am having 3.25's put in it as I write this. I want more highway friendly and I figure these will net me a few hundred RPM over the 3.55's.
generally, i'd go with 3.55's max if u plan to do any frequent highway driving. as John stated, tire size will be a factor as well. if you had an AOD or T5 (something with an OD gear) you could run a steeper gear like a 3.70 or 4.11 and still do great on the highway. anyways, 3.55 would be my opinion
I just put 3:55s in myself, and can't wait to get it back out on the road. I had been running 4:62s ... we have an 1/8th mile drag strip here, and those gears were stupid fun (they were almost free ...), but they were too much even for that track. The car was out of wind about 50 feet before the finish. (...need MORE motor... ) Cruising a 45 mph and only getting 5-6 mpg got old. Our cars are so light anyway, that a lot of gear is might do you any good only if you have a high revving smaller cube motor. I will bet that the 3:55s will ET the same as the big gear, with better MPH. 60 foot times might be a little off, but I am really looking forward to actually road-tripping in this car again.
i have 3.70's with no overdrive.... but i cant tell you how it drives as of yet, since its off the road for paint to finish the restoration.
Changing rear ratio is the biggest bang for the bucks. I was running 3.70 with 25" tires in my Falcon and it took 4000 rpm to keep up with traffic on the interstate. I now have a 3.25 and when I turn 3300 I can now pass a car or two on the interstate (driving my age). I know what the Captain means about stupid fun with a low gears. I had a 4.57 years ago and I could stretch all 4 gears to the red line crossing a 4-lane intersection from the red light. I mostly used 2nd and 4th gear on the street Being an automatic I think a 3.00-3.25 is all you need if you plan to drive any distance on the interstate. I know I have to ride my clutch too much to get it rolling with a 3.00 in my car. (gotta a lot of hills in Georgia)
At 70 mph it is running about 3200 rpm, the last time i drove it a long distance it go about 12-14 mpg.
ive had 2.80, 3.25s, 3.50s, 4.10s, and 4.57s. for what you describe i would go with the 3.25s. they cruse at freeway speeds below 3000rpm and still can jump up and go at a stop light.
yea Bryant is doing my rear! I'm going with a 3.25, still looking for a good 8" 5 lug for my 71. The last one had too much rust and the cleaning would have cost me a bundle.
If you Google "RPM Calculator" or some such you will find a bunch of RPM vs speed calculators, e.g., http://www.westerndiff.com/rpm.html Should give you a good idea of cruising RPMs with various ratios.
