I can understand you wanting to reduce RPM's at highway speed, but if you switch to a 2.89 rear gear, your car won't be much fun around town.

However, if you simply must have lower RPMs at highway speed, and you want to stick with your top loader, go ahead and install a smaller rear gear. I wouldn't bother converting to limited slip. With a 2.89 gear, what's the point?

You say you may go for big horsepower in the future. When you do, then worry about limited slip.

To change the rear gearing, you need only a new ring and pinion. No big deal. To convert to limited slip, you need a whole new gearing assembly. BTW, "Posi" refers to Positraction, which was a GM product. For a Ford, you have the option of Traction Loc, Detroit Locker or Truetrac. I installed the latter in my car and I would recommend that option. But again, not until you really need it.

 

Thanks for this. My desire for some sort of limited slip comes from exiting corners on twisty roads. Inside tire spins stupid easy. Hard to get a decent drive. Chirps around city block corners stupid easy as well. Plus when I do want them to make noise dual black stripes are just cool (not that I can do that with my c-code cam and heads)

If I go to 3.0 instead of 2.8 I get a less than 10% gearing change. I think I want more than this.

 

Based on what you want . . . you are the perfect person for a T5 3.35 swap. Have your cake and eat it too.

 

Except that I like the 4 speed. And I don't relish the thought of yet another tranny in my garage AND the other associated work needed for the swap.

The TL fits and works great -- would be nice to have a wide ratio. Thats the issue. Will it be wide enough? Maybe not. That's what I need to determine. Keep my present overall 1st gear ratio the same and bump up 4th by 15%. That is the goal.

 

stick with the toploader for all the reasons the OP mentioned. I think a 300:1 will suit you fine. I used that rear end ratio for years and really enjoyed the highway rpm.. You can get a lower 1st gear (2.90) to help with take offs, which is what I did. . David Kee transmissions has them. What diameter are your tires? If they are less than 24" you will be adding rpm per mph for no good reason. Closer to 25" diameter would be even better

I also added a vintage Paxton to help in the acceleration department, which is what it sounds like the OP is planning also, add HP that is at some point.

Z

 

Basically factory 4-speed toploaders came in two flavors: close ratio and wide ratio:

close: 2.32, 1.69, 1.29, 1

wide: 2.78, 1.93, 1.36, 1

You can get cu$tom gears for other ratios

Good luck
Paul

 

I have a early case toploader with custom gearing and a 28 spline
output shaft that I'm getting ready to put back in my '66 GT. It's
got 3:1, 2.01, 1.42 and a 3.0:1 rear gear. Gears are helical cut
tooth custom pieces, so the trans has some whine to it but not
much of an issue over the exhaust.
There's a few folks offering custom toploader gears these days;
back in the 80's when I got this spare trans done it was a pretty
pricey deal.

 

The big question is..... do you really have a Toploader or do you have a Toploader Imposter?

Does your TL have a tag? Is it tagged:

RUG BP
RUG CA
RUG CL
RUG CD

The other possibility, unless you are sure that your transmission has the external shifter with 3 rods on the side, is the later SROD 4-speed, which WILL feel like you skipped 4th and shifted into 5th when selecting high gear.

 

Where is the tag located?

 

OH it's still going to be pricey. Gears are expensive. YOu need the gears and the cluster gear . . penny up. I have several toploaders in vehicles. I like them too. But what you want . . low first gear and cruise ability is exactly why people swap the T5 in. Sell the TL and you will be in it for less than modifying the TL, IMO.

 

Ok, point taken. If the internals are really that expensive then the T5 may be the correct path.

 

transmission

Cita, get the 2.79 gears, and get some taller tires. Then your easy available gear spread choices are......3.01/2.08/1.47/1.00/R3.01 or 3.52/2.27/1.46/1.00/R3.52 or the deepest easily available 3.82/2.29/1.46/1.00/R3.82. You have to get the full gear set and drop them into your case. If you have the 2.32 1st toploader now, with the 3.25 axle, you launch at 7.54. If you swapped to the 2.80 gears, you would improve freeway feel, and the 3.01 1st in one of the swap sets would have you launch at 8.42. You'll shift sooner, but so what ? You'll be fine. Get out there and start looking for those other gear sets. Might be easier to find the whole trans, and then you swap the guts into your case. Easy. LSG

 

back in the day the speed limit in mississippi and other states was 70 mph. 3 speed autos and 3 and 4 speed sticks with 1:1 high were the thing. 2.79-3.7 gears were common. 3.70 gears in pickup trucks were common. ALL those engines ran in the 3000 rpm range and never had an issue. gas was 30 cents a gallon and 8 mpg wasnt given a 2nd thought. it will not harm your engine to run it at those rpms. Boss 302 , early sheblys and 65-66 hipo mustangs came with 3.5-3.91 gears and some had short 14" tires. my 2006 f350 has a 4.10 and overdrive trans and turns around 3000 rpm at 75 and up mph. unless you want to get better mileage it aint gonna matter. also its possible your mileage could go down if you lower the rpms. i had an 86 toyota corrolla that get better mileage on the highway around 55 with the overdrive off.

 

"……..it will not harm your engine to run it at those rpms. Boss 302 , early sheblys and 65-66 hipo mustangs came with 3.5-3.91 gears and some had short 14" tires. …….".

the cars haven't gotten soft, the drivers have. I have a Sports Car Graphic magazine (best car mag of the era) from 1965 and they did a 10,000 mile road test of the 1965 Shelby Mustang which had 3.89:1 gearing. They drove from coast to coast and back again, the long way. There is no whining in the article about the highway rpm being too high, they just drove the hell outa it, and had a gas doing it.

Z.

 

If you think the internals of a top loader are expensive, just put in a T5 and then add your increased power in the future. When the teeth start coming off the gears like corn on the cob at dinner time , then you'll get a good idea of what expensive really is.

You (supposedly) already have the strongest transmission. Ford ever made, play around with a lower first gear and some alternative rear end gearing. You will be a grand or two ahead once you get it sorted out to your satisfaction.

Z

 

Well part for part, the toploader is more expensive.

 

transmission

Cita, what do you consider pricey ? The ratios I listed are factory options. You get get the whole trans for a $200-300, swap the gears into your case and you're done. LSG

 

I agree the T-5 would be your best option. However, for info, parts etc. for your toploader: David Kee Toploader Transmissions, Inc.

 

Toploader

It's not clear what transmission you have, WR, CR or 3 speed w/overdirve (toploader imposter)

One unmentioned option is a Gearvendors unit, pricey, but solves the problem while keeping the Toploader

 

What about keeping what you have and attaching a Gear Vendors OD to the back? I think they are pricey but might get you what you want.

 

Just a couple pennies from the peanut gallery -- I recently learned that if you want to use the Eaton Truetrac you need to have at least 3.25:1 gears in the differential. For ratios numerically less than that the pinion is larger and interferes with the Truetrac carrier.

 

trans

You guys are making this way too hard. And expensive. A 30 second Craig's list search finds a T-176 Jeep trans, ( the 3.5 1st gear ) for 300$. Swap the guts into your housing and done. Yes, it really is that easy. LSG

 

You guys are making this way too hard. And expensive. A 30 second Craig's list search finds a T-176 Jeep trans, ( the 3.5 1st gear ) for 300$. Swap the guts into your housing and done. Yes, it really is that easy. LSG

That's interesting. Pretty wide spread too.

To the OP what are you really going to do with the car? To me it sounds like a cruiser, kids and all. Are you really going to add loads of HP somewhere down the road? While it would be fun are you prepared to make it a 400Hp+ car? Suspension upgrades, subframes, 9 inch......

Or is it something to be enjoyed just driving around, family cruises, etc?

Get the tag number off the trans. Then you know what you're starting with. If you have a close ratio then just going to the wide ratio will make the car easier and more fun to drive, especially with the 289. If you went to wide ratio with a set of 3.00 you woud still have mre starting line grunt and a lower freeway rpm. When I had 3.25's I never had issue with freeway RPM though. Yeah, engines ran with that and way more back in the day. Wasn't uncommon to see 3K plus on the freeway. Of course those engines needed rebuilding at the 100K mark, nowadays 200k is pretty common. Thank you overdrive and EFI. Sure, some folks made it 200K plus with their 4.30 geared car but that wasn't the norm.
I'm with Pete on this, an ideal swap is the T5. I see those on Craigslist also for 300. But you can get a brand new one in there for about 2800. I'll bet 500 less if your resourceful getting the parts, enouugh people have done the sway that used stuff shows up frequently. If you want to take your chance with a used trans I'll bet it could be done for less than 1000. Yeah, pricey. What's it going to cost to do rear and redo your current trans with different gears? I'll bet it hits the 2000 mark. On the other hand, you might find the freeway RPM too low at 60 with the T5 and your 3.25's, 70 might be your preferred cruise speed.
People are right, T5 is not the strongest thing out there, but it will live a long life behind a mild 289. If you're out doing 5K sidesteps, not so much. But for some fun spirited driving, yeah. If you need stronger there is always the TKO, but that will be much more pricey. I'm like you, LOVED rowing thru the gears with the toploader. But once I got the 5 speed in mine I never looked back, and I drive the car a lot more often. Get's better mileage on the freeway, around town about the same. Maybe less, more fun to drive with the better gear spread.

 

I do things once, I am going to have an Astro A5 put together for behind my 347. Takes 550hp/485tq. I have been searching the web for about 2 weeks to try and find someone that has broken one, and spoken to 4 different dealers from the West Coast to the East. I have not heard of anyone breaking it. G force t5? Yep lots of broken gear sets, especially 3rd. For another $400 you get a hardened main shaft and it pushes it to 650/550 for the A5 (which is pushing the boundaries of the case).

Net gain BUILT T5 vs a t56 or TKO: Similar pinion angle to stock, similar weight to a Toploader, .60 overdrive (4 gears for go, 1 gear for cruise), no tunnel or trans hole modifications, and you can run damn near any rear gear that you want (I have a 3.89 Detriot locker 9" currently). I will spin 2300rpm with a 275/35/18 and my current setup in 5th at 75mph, 2150 at 70mph. And you keep the smooth shifting, which you will not have with a TKO or T56 (unless you drop another $700 on the TKO to make it shift better. $3k+ no bell or clutch)

This is not a cheap option, but I will be losing the Z bar (removing both steering double D and header clearance issues), installing a hydraulic clutch, gaining 10mpg on the highway for the family trips, and allowing "factory" type interior components like consoles to still work in the car. I figure I will be all in for about $3800 with an aluminum drive shaft.

I will sell the toploader and nice Mcleod clutch with bell for 40% of that upfront cost. (she is not stock by any means heh)

All depends on what you want to do. Making the car less fun to drive seems to me to defeat the point, upgrade to modern tech, gas isn't 30 cents a gallon anymore.

Fej

 

My car is a numbers matching 66 k code car with a 3.25 geared 9 inch with CR 4 sp. I too wanted less revs at highway speeds. Because engine block, trans case are serialized to the k code vin of the car, I wanted to do this just with a wheel and tire package. I had American Racing build me a set of 4.5 inch backspace TT's in 15 inch diameter wheels and mounted 205/60-15 on all 4 corners and the tires reduced 65-70 mph on the freeway by about 300 rpm,which was a lot better than the factory 14 inch magnum 500 that came from ford when car was new. What a difference from the 6.95 14's that the car came with!

 

I have spoken to this before, but it needs said again . . . close ratio verses wide ratio is NOT just about "take off ". That is not why the two different transmissions were developed; for takeoff. It is about matching critical engine speed when shifting between ALL gears. Close ratio is superior in that situation, in most cases. It does depend on your engine build, but by far the CR will keep you in the "sweet spot" better than a WR transmission. That is why they were developed. It does mean the rear ratio should match this setup as well. And you can't be one to worry about RPMs on the highway. As I have said before and a couple posted in this thread already . . people didn't worry about the engine RPMs as much as they used to do. Unless you are using it as a DD . I don't see the worry. An OD is nice, and lets you have it both ways, so to speak. But relax on the worry about RPMs.

 

I run a wide ratio Toploader with 2.8's and 225/60/15 tires that are about 25.6" IIRC. No problems starting off and runs real nice on the highway. Tall enough to cruise comfortably but low enough that I don't have to downshift for hills. I like the combo.

 

Thanks for that data point. Finally, someone with the exact setup I am considering.

I do not need close ratios. I don't care if engine output drops 20% when I shift versus 5 or 10% with a close ratio. In fact with the ratios I have now I very often skip 2nd gear in normal around town traffic. The spread from 1st to 3rd is easy for my 289 -- if I am not in a hurry.

So I see a couple of top loader wide gear sets on ePay for about $200. Bearing and gasket rebuild kits for another $100. I get to keep my super strong top loader going this way and if I should want to go crazy with a 347 down the road I still have the right tranny. No new tranny mounts, cutting on the tunnel, modified clutch actuators, new drive shaft, etc or a bunch of parts hanging around in my garage (at least any more than I already have!).

my basic goal, really, is to keep 1st gear where it is and raise 4th by 15%. -- oh and toss limited slip into the mix if possible.

So I will check this weekend to see if I have a "real" TL 4 speed.

 

i saw a 65 shelby with L78-15 tires. thems the size they put on huge cars like cadilacs way back when.

 

Gotcha, thanks!

 

transmission

Pete, you're exactly, um, wrong. It IS about takeoff, and yes, thats why the wide ratios were developed. The close ratio is only helpful in a few racing situations. 99.9 percent of us, including drag racers, are better off with the wide ratio setup. If you look at new cars, compared to ours, you'll also notice the spread between gears is getting progressively wider. Our man needs the tallest rear tire he can get, 2.79 gears, and the T176 gear set. Highway rpms will drop, and the new 1st will give a tremendous launch at 9.82. No downsides.

Think about how lots of cars came with 2 speed auto for awhile, and then the 3 speed autos had 2.48 1 st gear, then in the 90s, Ford's AOD got a 2.84 first------it is all about takeoff, while maintaining good economy. LSG

 

Pete, you're exactly, um, wrong. It IS about takeoff, and yes, thats why the wide ratios were developed. The close ratio is only helpful in a few racing situations. 99.9 percent of us, including drag racers, are better off with the wide ratio setup. If you look at new cars, compared to ours, you'll also notice the spread between gears is getting progressively wider. Our man needs the tallest rear tire he can get, 2.79 gears, and the T176 gear set. Highway rpms will drop, and the new 1st will give a tremendous launch at 9.82. No downsides.

Think about how lots of cars came with 2 speed auto for awhile, and then the 3 speed autos had 2.48 1 st gear, then in the 90s, Ford's AOD got a 2.84 first------it is all about takeoff, while maintaining good economy. LSG

Sorry to say you are misinformed and not seeing the entire picture. The close ratio trans is to keep the rpms at a level, as you shift through all gears, that is within the sweet spot of the engine. A wide ratio trans causes too much of a drop off in rpms between gears. That is why they were developed. However, it's more specific, thus the wide ratio for everyday cars. This is why . . . and now you know the rest of the story.

 

Not familiar with that cams power curve, but with a Ford HiPo cam, or the Weber friendly ca, I'm now using, there is plenty of torque at 2,200 rpm which equates 60 mph with the 25.4 tires and 2.80:1 gearing mentioned .

Still, I'd be recommending a 3.00:1 rear end, and the stock wide ratio toploader other than a 2.90 1st gear.

Z

 

the fewer the gear changes the better