Are 2.88's just too high for the street?

I have been looking at the Jag rear ends, and the cars I've been looking at I *think* are all going to have 2.88 gears. I don't want to buy new gears right away to get the truck on the road, but want the ride (and lowering) of the Jag.

Would 2.88's be miserable? I was thinking of putting it behind a 5 or 6-speed manual. The Tacoma 6-speed has a pretty low first gear, but I'd rarely get into 6th with it.

I think the 6th gear is about .85, so with the 2.88 at 2,000 RPMs at the crank and a 29" tire you'd be just a fuzz over 70MPH. The local highways are all 60-65MPH, so I wouldn't see that much locally.

Would I be better off getting a solid axle rear with a better gear ratio? I'd probably change gears down the road, but who knows when.

 

What kind of power plant? And estemated HP? What type of car?

 

All depends on your tire diameter and your cam. I ran 2.88 and 2.80s in several cars. One was a '66 Falcon 289" and a three-speed synchro toploader. The other was a Sunbeam Tiger with a 2.32 close ratio toploader

Just yesterday I drove a Sunbeam Tiger with a T5, 15" tires and 2.88 gears. It was a really, really great street combo with a 302" and a 280-degree cam. It's a light car, but even with the highway gears, it was still rocket ship.

jack vines

 

It's a 1950 International L-112.

I haven't decided on a motor, but the original is pretty well done. If I rebuilt it, a solid 90HP @ 3600 RPM (redline). Its either going to be a straight 6 or a V8.

I've looked at everything from Chevy and Jag I6's to IHC and Chevy V8's, both old and late-model stuff. So, I guess that's anywhere from about 150-375HP LOL.

 

Some of the mid 1970's borge warner t-10 transmitions had a 3.44 ratio first gear and a 2.88 second. It would get things going.....

 

The Tacoma transmission I was thinking about should have these gears:

6 Speed Manual
1st = 4.17
2nd = 2.19
3rd - 1.49
4th = 1.19
5th = 1
6th = .85

It shouldn't have any issues with that first gear, but it's quite a drop to the second. I don't know if that's even a possible transmission.

 

gears in the high 2s work ok with a non-overdrive transmission, although with only .85 overdrive, if you had a torquey engine it could work ok. But not with the original old six.

I have no idea what engines a toyota transmission might fit.

 

Me neither, I need to do some research.

It's not a very HAMB-friendly motor, but Chevy's LL8 Vortec inline 6 is intriguing. Almost 300HP if you get an '08-09, would fit real nice in the truck. Exhaust stays on the p***enger side like the original, so you don't have to fight it for the steering shaft.

I mention the LL8 also because some guys have apparently swapped the LL8 into older Supras without too much trouble--so maybe Toyota shares some bolt patterns?

My uncle has what should be a decent Chevy 250, that if I can get it out of his truck and shipped I could probably have that cheap. He also has a V8 I can have, from my aunt's 4-door Impala. It was probably a 67-70-ish. He says it's a four-bolt 283, so I have no idea what it is!

I'm half way across the country from his motors, so logistics is an issue.

 

Just get a better ratio rear end.
They come in:
post '82
2.88
pre '82
3.08
3.31
3.54

 

I'll see what I can find. I found a couple that I was looking at buying the whole car, as it was probably as cost-effective and there are some other parts I could use off of them on the truck. However, they are all post-'82.

I was actually kind of toying with even using the Jag motor bolted to a manual trans. I gather they are really expensive to rebuild though, probably more than any domestic I6.

 

Could be a 283, 307, 327, or 350. Only the 350 could be a 4 bolt main, but not if it was in an Impala.

The 250 might be ok, not much for power but would probably work good with the stock truck rear, with or without overdrive. Without OD you'd probably be speed limited to around 60-65 mph.

 

3.77:1 came in Jag S type and 420G models with 4 spd o/d - I had a 3.77 in a model T many years ago. I have several 3.54s - look for a 1970s XJ6....

 

I thought 2.88s came in early XJ40s... You don't want an early XJ40, well, it's not the Jag IRS that hot/street rodders know. Those are economy gears anyhow.

The Jaguar inline I6 is a good engine and with proper care will go to 200k. That means ANNUAL coolant changes, NEVER EVER EVER run straight water, and 15W40 or 20W50 Castrol GTX every 3k..

Engine stuff ***umes were 1987 model year (us) and older.

 

The two cars I am looking at are '85 and '87 XJ6's. The '87 says it has a "burnt valve". The '85 I guess drives nice, but is almost 2x the cost (both are cheap). One place said all the Series III XJ6's were 2.88's, and others that just said post-'82.

There are shops and places that sell the IFS/IRS, but for the cost of a couple I've found, especially if I used the motor, it would seem better to use suspension from a driving car than something buried in a s**** yard for 20 years.

There was one that sounded/looked real nice, but the person obviously loved it and wanted it restored. They'd probably have a heart attack and refuse to sell if I told them I wanted to hack it up. Though I would have a hard time hacking up a really nice car--even if it wasn't my thing.

If the car is pretty worn, is it worth trying to rebuild the motor? Are the later 85-ish cars EFI'd?

 

http://www.uk-hotrods.co.uk/v2/tech/jag_rear/tech_jag.php

 

With some low-end torque the 2.88 should be fine. I ran 2.73s in a 350 powered truck for years - with overdrive at that - no idea why it was ordered that way but I even towed stuff with it and it was fine, if no dragster.

 

The 4200 isn't really torque enough for 2.88 AND overdrive, unless the car has no frontal area, you're running really short tires, and / or you don't mind cruising at 90.

You might be able to get it to do that with boost, but you better have excellent fuel.

If you were running a diesel, maybe.

Figure what engine speed you want at what cruise speed, with your tire sizes and work the math backwards to see what rear gear you need.

Slower engine speed will generally be quieter on the road, but will usually require an engine with more torque (so more displacement or at least more stroke, so maybe a 302 Jimmy? ).

 

Wish I had gears that tall, I'd be running 90 on my little 14's everywhere!

 

get a ford 8" rear

 

Millions of cars of many sizes were sold by the Big 3 with 2.73/2.75/2.76 gears. If you got enough engine the car will still get off a red light well & the O/D is only of use on the highway. Rear ends like 3.50-4.11 will still get poor milage around town as if you didn't have the O/D. Just a matter of how much highway time you spend & what you want to do for around town driving.

 

I have a basically stock 350 with Vortec heads, in my '40 coupe. (see avatar). Ran a 700R4 and 2.75 rear for years. Performance was O.K. and I averaged between 24 and 27 MPG on the highway. Rear went bad and I switched to 3.55 gears. Faster off the line alright, but I haven't had it on the highway long enough to check mileage.

 

Id forget that toyota trans. I have one in my toyota truck and it kicks ***! But their kinda rare and worth quite a bit. Id be worried about putting it behind a v8. I ripped the center out of the clutch on a hard shift a few months back i doubt there is much for adapters for them as they are not that plentiful. But try Kennedy adapters.

 

If you go for the 250 I ran a 74 250 with a full syncro Saginaw 3 speed and a rear end pretty close to the 2.88 in the 48 for years. It was rather whimpy off the line but would cruise at highway speeds and pulled 20 mpg on road trips.

If most of your driving is short trips and around town you probably won't like the 2.88 gears though.

 

I think the LL8 is pretty much out--especially with the tall gears. If I were to supercharge it, it will be well down the road. I guess I'm probably looking at a V8 of some sort.

Where we live now, getting around anywhere pretty much means getting on the highway. So the highway is used a lot, but not much over 65 usually. Only when we go out of town or something, which will probably be done in the 4Runner more often than not, since we're probably headed camping or something. I'd drive it if we were headed to a show or something though.

How much can these Jag rears handle, HP-wise? I'm not sure it's very much. I really like the idea of using them to lower the truck without notching the frame and stuff--it still needs to be able to haul light loads and stuff, but needs to mostly be a cruiser and driver.

I was worried the Toyota trans would be hard to find and expensive. I guess I'll forgo that one.

 

I got away with running a set of 2.29s in a 3300 lb 50 chevy delivery but I picked a saginaw 4 speed ****** with a 3.40 first gear and the engine was a torquey 406 cu in smallblock with a mild cam.
I also used a big 12 inch pickup truck clutch. It was a pleasure to drive in town with the low first/second gears and in 4th gear it'd run about 1800 RPM at 70 mph...ran cool and got fair gas mileage with big 285/70R15s..a 30.5" tall tire.
No problems for me.

 

The Jag uses a Dana 44 center, doesn't it? that's pretty stout, similar in size to the better 10 bolt chevy rear. Although it has those half shafts and stuff.

 

It might depend on how tall a rear tire you run. I found that a 3.08 worked fine in an A coupe w/an SBC.
2.9 is pushing it if you've got any low speed/traffic driving planned though. Definitely would want a low first gear.

 

Correct me if I'm wrong......
A XJS has 2.88 posi, and the V12 makes around 300hp and 300 ft lbs w/OD.
The XJS was not a slouch IIRC.
How about a 292 six making 300hp and 300 ft lbs and a manual 3sp OD.
Cars weighing about the same.
Should make for a nice fun road car I would think.

 

I run a 273 with a 350 and a non overdrive 350 trans in 32 vic, and it's pretty slugish in town, but on the interstate the sky is the limit, if i ever go to the salt i got the rear end. !

 

I drive an OT Crew Cab with a Quick Change rear end. Originally it came with a 4.10 14 bolt. With a stock 454, turbo 400 and 29" tall tires I have run 3.65, 3.08 and currently a 2.42 rear gear. I just kept raising the ratio, thinking that I would find a point that the truck just wouldn't pull anymore. Haven't gotten there yet. Mileage went from 9mpg to 13.25 (real numbers, highway, no load). I don't think I would want to pull a trailer or load the truck with a pile of oak firewood with this gear but it runs fine around town and down the highway.
Our hot rod heritage tells us that we NEED steep gears to maintain decent acceleration. How many stop light Grand Prixs are you really going to compete in. If I were you, I wouldn't be afraid to use the LL8 with its' original automatic transmission and a 2.88 rear gear. It has a great 1st gear and that engine has enough torque to maintain road speed through RPM drops during upshifts.

Now, if somebody has #58 Winters change gear set (or the equivalent) I would be glad to try a 2.19 in my CC and report back.

By the way, back in the day I had a '55 Chevy with 5.13 gears and 28.5" tall slicks. I know what acceleration feels like.