Rear Gears for a 514 with a Top Loader??

[David Kidwell]

Can anyone give me some suggestions on rear ratios using the
514 and the small spline Top Loader. I belive that 3.73s are too low for this tranny. Is anyone running 3.08s or somewhere in between??Thanks for the input!!

[bmalone]

If you have a WR top loader, a 3.31 rear is a good choice for street use. WIth a CR, you might want to stay at 3.54 due to the taller 1st gear. I run 3.54 w/ a CR, and I like it. You cruise at about 3400 on the fwy. with this setup.

Remember, you have a ton of torque and a light car, so you can be fairly aggressive with high gearing.

[Bob Putnam]

David,

You can easily carry 3.31 or even 3.07:1, assuming that your Top-loader has the typical 2.54 first gear and your engine isn't totally tweaked out.

The original street 428-engined cars with wide-ratio Top-loader used the 3.31 gears.

[Tom Wells]

Hi David,

It depends...

I have a "toned down" 521 in a car that I guesstimate at 2650 lbs, with a C6 and a 2200 rpm stall converter behind it.

I can do burnouts of the 315/35-17 rear tires at any speed up to about 100mph using a 2.88 Powr-Lok Jag rear.

So if your engine has some "low end torque" (you'd have to work hard with that size engine not to!) a pretty low number axle will do.

At least that's my experience

Tom

[David Kidwell]

Thanks Bill,Bob,&Tom for your replys.Have not had that much to do with gearing in the past. Run my vette in third{auto trans} most of the time even at highway speeds but the 350 is pretty sluggish even at that. It has 2.90s and will hardly burn out at all!!!

Hey Bob, I have not had the pleasure of knowing you have been working with Peter. I would like delivery in mid Nov. don't let him snooze on me OK...

David "Dakruzer" K.

[Back in Black]

With gobs of off-the-line torque ! You should be running a 3.00 or higher gear in my opinion...3400 seems excessive rpms to me at freeway speed.

I chose the Richmond over drive 6 speed and 3.00 gears...probably won't have a lot of use for the 6th gear, but off the line torque is not something I am worried about with the 514

Was over at Car and Driver reading articles, thought this might be of interest...keep in mind that your Cobra will have MUCH higher HP to weight ratio..meaning anything said about the Viper's power in this article goes double for your cobra!
http://www.caranddriver.com/xp/Caran...Viper&class=20

[David Kidwell]

Back In Black, Thanks for the input!! Also enjoted the article very much...........I'm getting excited. Are you running a Jag rear unit??
Have fun with your new ride!
David Dakruzer K.

[HighPlainsDrifter]

David;
I run a 9" with 3.25 gears and a c-6 with a 2.4 1st gear ratio. I have no trouble lighting the tires all the way thru 2nd gear. With 500 lbs of torque you can run even higher gears, I'm thinking of going down to 3.00 gears. My cruise rpm is 2,800 @ 70 mph and can easily do 140 on the top end. If you run 3.73's you'll be rpming to much for all that beautiful torque.
Perry.

[A Snake]

David,

Just one more opinion for you. According to your "byline" you have an ERA. I would assume a Jag rear. If so, unless it's been changed,the most common gearing is 3.31. Frankly if that's what it has, I'd leave it alone. 1/3 of a ratio really doesn't make that much difference with the stump puller you have for an engine.

I was going for originality and put 3.73's in my car with a fairly warm 427 S/O. I didn't like it at all and absolutely didn't need the low gears.
Due to the builder of the rear end's idiocy, I had to rebuild it. I went to 3.54's and loved it. I think now, I would have liked the 3.31's even better. In my case, with my particular eengine, 3.00 or higher would have made the car soggy unless I was going 100mph or better and up in the hp/torque curve.

You have enough torque at low end to repave a highway with!! Especially in a car as light as a Cobra. I would go between the 3.31 on the low side to 3.00 on the high side. Any higher and torque or not, you'll lose some of the throttle snap in the lower rpm range. Any lower and you will be buzzing the motor needlesly. If you already have the 3.31's run with it. You can always do like I did and change later if you don't like it.

Just my two cents worth.

Al

[David Kidwell]

Al, Thanks for your 2c worth! From what you and everyone has said I have about desided on the 3.31s. I have not taken delivery on the ERA yet (Mid NOV.) so I had not committed on the rear. Was thinking the Jag was too light for the 514 but it seems a lot of guys are going with this combo?????What is the "outside"for this rear in terms of weight, HP,torque???

Regards David Dakruzer K.

[A Snake]

Y'know David, I gotta say, they're hard to break! How much the Jag rear will take I couldn't say. My engine made just under 500hp and more than once I did "drag race" starts with it. You know, dump the clutch at 4000 or more. I had Goodyear Bluestreaks on it which are pretty sticky.

That Salisbury diff. is almost a carbon copy of a Dana 44 "powr lok" and all. The carrier is a 4 pinion unit, the clutches are steel and the ring gear is 8 3/4". I've seen them really abused in sand drag jeeps and survive the experience. Most guys broke axles before the center would let go.

Short of 12" slicks and a 5000rpm dump of the clutch, I think you'll not have much to worry about.

That doesn't mean you can't break it. It just means you'll have to work at it. Frankly, I'd worry more about the Jag half shafts than the diff. itself. You might want to consider changing those for the fabricated style like a 'Vette has. (looks just like a drive line) Just make sure they are EXACTLY the same length center to center as what you took out otherwise you'll have a deuce of a time getting the camber set right. Been there, done that...got the tee-shirt! Ain't fun.

If you do consider changing them out, you might just have ERA do it at the factory. It could even be that ERA already does swap them out. Ask Bob.

Good choice on the 3.31's

Al

[Back in Black]

My car is getting final paint this monday/Tuesday...will have it in about a month...

I have a Ford 9 inch pattern rear...with Strange Engineering posi center section and 33 spline Pro Street shafts...good for about 1000 HP ! Pics in my gallery

I have to agree that if you have 3.31 gears, and there is no easy alteration at this point...try 'em out first...!

You can always go to an aftermarket "bulletproof" rear later, if so desired, in your flavor of ratios.

[bonyhadi]

ERA is a great choice. I have a wide ratio
top loader with 3:31 Posi and Auburn Pro Limited slip and Chrome moly stub axles -
handles all the horsepower the side oiler can
make.