I have been looking for a 9" rear for a '28 model A sedan project that I have a 350/350 drivetrain lined up for. I have been having a hard time finding one but just found one geared 3.55 for $250. I'm looking for good cruising and performance. Someone told me I should look for something in the 2.76 to 3.02 range? Is a 3.55 a bad choice for what I am building?
It should be fine,especially if you are running a tall rear tire[26-28"]and don't plan on running 85+mph for long trips!! JMO,ROY.
A 3.55 is OK, but many would be happier with that along with an overdrive. For that money, I hope its not a junk yard part. It should be a fresh rebuild with reciepts. Also, be sure the spiders will accept your axles, or make sure you have the correct spiders to put in.
For years I ran a 3.70 gear ratio in my 27 with a 29.5 tire and it was just about ideal. Made lots of interstate trips with it and the rpms weren't bad at all. That was with a straight stick with no OD. Don
I'm running something along the line of 3.00 (I did the turn the wheel and count driveshaft rotations method) in my wagon and it's the perfect cruise gearing for a trans that isn't overdrive. It's a 360/727 Mopar combo but it's close enough for what we are talking about. Tires are 225/75/15 which should be factored in as well. HTH, NAES
I just swapped my 3.50 out for a 2.73 in my ford 9". I'm running a 205/75R15. The car was very driveable and could go anywhere, but personally, I got sick of spinning 3000 rpms, burning a kuwaiti oil field everytime I took a long trip, and getting passed doing 62 mph in the right lane. Not to mention the added time a long trip takes going slow like that. If you can get an OD tranny, then by all means the 3.55s will be perfect. But for a standard 1:1 final drive, it's a real joy on the highway with the longer legs of the higher gear.
Oh, It'll be TERRIFYING. Screaming along at 25-2600 rpm, "jackrabbit" starts, squealing tires, children crying, dogs running for cover, old ladies and HAMBers looking on in shock and bewilderment, muttering about "those goddam crazy hot rodders" ect, ect.
I ran my 31 Ford PU with a warmed 283 / TH350 / Ford 8" 3.55s / 29" tire. It was liveable and gave it a little pep in town.
There are a number of engine speed/gear ratio/ tire size calculators on the net that all seem to work but you might take a look at this one. http://vexer.com/automotive-tools/speed-rpm-calculator Plug in the tire size and drive ratio of the trans and you can see what rpm you can expect the engine to turn at a certain speed on the road. These days most of the guys running 3.55 or 3.70 gears are running an overdrive trans to get the best of both worlds.
In a "hot rod" you will be happy with 3.55, if it is a cruiser you would be happier with 3.00. If you are one who checks you mileage go with 2.73
i have 3:50s in mine,,,,with a 26" tire it turns 2800 rpms at 65...getting ready to change to a 28'' tire and will go to a 3:70-3:90 gear...
Either your tach or speedo is off a little or your tire is a little shorter than 26", cuz you should be seeing 2940 RPM at 65. With 28's and a 3.7 you will be at 2886 and the 3.9 will be 3042
My first car was a '55 Chevy 2dr post bel air with powerglide and 3:55 gears. cruised down the hiway all day long. Don't remember the tire size, but it had to be pretty close to stock back in '61.
seriously? Have you paid for anything to get it rebuilt lately? or bought any parts? $250 for a complete used 9" rear is pretty reasonable these days. As for the gear ratio...kinda depends on what your idea of "cruising speed" is. If it's 65 or less, you might be ok. If it's faster than that, you probably want less gear, or overdrive. But it also depends on how far you're going, if you won't venture more than a hundred miles from home, you'll be fine.
3.55's are for 8" rear ends, 3.50's are what 9" rears came with. I have 3.50's in an off topic pickup with 29" tall tires, and I hate it on the highway. First set of 3.00's that I find are going in it.
3.55s are what early 9" rears came with. If it's really a 9" with those gears, they're probably really old....
No kidding. New Ring & Pinion $150-200.00. All new bearings, seals etc, $100-150.00, Labor $100.00 and up. It adds up pretty damn quick
My 28 Tudor has a 396/th400 with no overdrive and a 29.5'' tall tire. I had 3.50's and switched to 2.75's because my club does alot of super long trips and I thought it was a good idea. I got 17 mpg on our last outing with the 2.75's... but I hated it. Sure I could go a billion mph if I had the balls to do it, but Its hard to smoke those tall tires even with a bbc! Im going to try somewhere in the middle next. I think around 3.00-3.25 would be the perfect ratio for the best of both worlds in my opinion.
I am running 355"s in my 55 with a 302 C-4 would not want to tryin cruz at 80 .little 302 with 650 carb aint bad on gas and will churp second dont scream but runs pretty damn good
While we are on the subject- I have a Ford 9" with 3.50 Gears. '85 Camaro T-5 with 3.50 1st, .78 5th. 29" tall tires. I'm guessing around 150hp, 2500 pounds. It'll be mostly in town driving, with some long trips. My friend is looking for a 3.50 and he wants to swap me his 3.00 Would I be better off keeping the 3.50 or should I swap to the 3.00? Sorry for the hijack, but I have had this question for a while and it's seems to kind of fit.
Just my 2 cents with my lo po 350/350 combo in my shoebox ford I've had 4.10, 3.31, and 3.0. By far I like the 3.0 the best, but honestly wouldn't mind 2.79s. I have 205/70/15 I think. With my cheap ass hockey puck tires it would spin like crazy off the line and low speed turns, really had to feather the throttle until I got the 3.0 maverick 8" The lower gears were nice when it came to braking and I had all drums. Boy did they slow it down decelerating! Is there any reason you need a 9"? If it's not a reallly high performance engine, maybe you could find someting else cheaper and iwth the gears you want? I think my neighbor wanted 600 for his 9".
I'm driving a 56 Dodge 1/2 ton pickup with a 8 3/4" Sure Grip rear....the gear ratio is a freeway friendly 3:23.....There's plenty of punch off the line and I'm able to cruise at 65-75 with no sweat....I don't have a tach, but the engine seems happy on the freeway...good MPGs too with a mildly warmed up 318 and Torqueflite.
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