Just finished a 4 year (my first build) 29 Ford Roadster, with a 302 and an AOD out of a 85 Crown Vic...the rear end is out of a 94 Mustang ( I think it is a 273 ratio ...problem when the over drive kicks in it so low geared that rpm's drop to about 1200 at about 55 mph...question? Will it hurt to run it in the lower drive gear (not going into overdrive)? or if I was going to change the ratio on the rear end, what ratio should I use? Appreciate any help...
I'd suggest you don't use overdrive in Drew County because there's not enought room for that speed. You really need deeper gears in the diff. 3.55 or 3.73 gears will compliment the .66 overdrive ratio well. I might be able to help Hoyte and his boys with helping you if you know Birch.
I know of them...you are right in Drew Co there isn't enough real estate...my guess is 3000 rpm would equal about 100 mph...I like the idea of a 3.73. Shouldn't be too much of a project would it? thanks for your help.
You've probably got a 3.08 gear in that axle. You'll definitely need to go up to a 3.73 or 4.10. Will really help the car get off the line too
My F100 has AOD with 3.92 rear and 30" inch tall tires. About 2200 rpm at 70MPH. Performs well thru the gears.
I run my roadster (302/AOD) with a 3.90 rear gear and 30 inch tires. I don't put it in OD until I'm rolling at least 60 (2600 in third), but it cruises great at freeway speeds.
#1 make sure TV cable correctly set up with a pressure gauge. search online for : project33.com and click on calculators-has easy to use info for figuring out gears to use with your trans/tires
You could drive the car in D (3rd) locally and save overdrive for the interstate. A '29 roadster turning 2000 rpm at 80 mph should get great mileage on the freeways. However, one thing to be aware of is that the torque converter probably doesn't lock up until 1700 rpm or so. That means that you are generating alot of extra heat and wasting gas if you drive it in OD below that rpm.
I believe the '85 is still the rod operated version. A Crown Vic Police Int I had was 3.08 & AOD, but had the 351W. Moved fast enough for the cops!
My 33 has a 5.0 F.I. out of a 92 Mustang with A.O.D. w/255/70/15" tires and running a 411 Mverick Rearend = Transmission Shop guy worked out the combination ,works perfect for me,shift into O.D. above 50 mph.
I run 3:55 gears ( 235/70-15) in my coupe with a 700R4 . With the converter locked up and in OD the SBC is turning 2000 at 60 mph
2.73 and 3.08 were the common gear for a 94 Mustang GT 5 speed. 3.08 and 3.27 for the Automatics. If the tag is still on it, post up the info and I can tell you for sure. And to answer your questions, NO it won't hurt it to drive in 3rd and we can't really suggest a gear ratio without knowing how tall your rear tires are.
thanks to all for the information, let me measure the rear tires this weekend and get the tag # off the rear end.
I had a couple daily driver 80s crown vics with 3.08s and a AOD and they seemed to do ok,trans usually never goes into o/d untill over 45.
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