Red Dog

Hello and thanks for letting me post. I am new at this so......here it goes. I owner a 1971 442 convertible, it has the original 455, TH 400 and 3.23 rear end. My mom ordered this 442 and I got it in 1977 with about 75K miles. I had the engine rebuilt in 1994 and it has about 20,000 miles on it since then, it runs well. The rear end has not been out of the car. My question is what to do with the transmission. The original TH 400 was re-built in 1994 and it shifts tight, except for a few leaks. I have started the 2nd major restoration and would like to have overdrive for improved highway drive ability.
Does anyone have a suggestion for an overdrive that requires the least amount of modifications. 344671M179031

oldcutlass

Welcome to the site, post some pics when you get a chance. My opinion on overdrive transmissions is if your not driving it all over the place mostly on the highway, money can be better spent on something else.

anthonyP

PM sent.

Qwik71442

Gear Vendors Overdrive

joe_padavano

The 200-4R is the easiest swap but you will need to have one modified to live behind your 455. Expect to pay close to $3K for either that or a Gear Vendors. The 4L80E is the only OD trans strong enough in stock form, but it requires floorplan mods, a bellhousing adapter, and an expensive ECU.

11971four4two

This is what I would opt for. Gear vendors are a few $$$ and require driveshaft mod. Nice way to fly and have basically 6 speed transmission.

Otherwise you could try a 3.08 or 2.73 rear gear ratio / and / or a taller rear tire I have been using 255/60/15 mickey thompsons on a couple of my cars.
Have Fun

BangScreech4-4-2

A lot of your car's value is in its originality. Give that serious consideration before you go do anything that can't be easily undone.

OLDSter Ralph

Simple words of wisdom worth considering.
Ralph

Cutlass Fan

What about a 700r4. Isn't it basically a 400 with overdrive? If so it should handle the torque. Not sure on mods needed ie trans mount and drive shaft.

Charlie Jones

Gear vendors overdrive , approximately $2500 plus installation cost .
Average use of a "collector" car , maybe 1000 miles per year.
Approximate cost of gasoline $2.50 .
The best savings on fuel mileage with overdrive perhaps 5 MPG .
5 MPG / 1000 Mi. =50 gal. X 2.50 = $125 / year.

$2500 / $125 =20 years just to get your money back ! Before you save ANY money !

Save your money and buy gas!

joe_padavano

No. The 4L80E that I mentioned above is a TH400 with an extra OD gear set. Unfortunately, that extra gear set makes the 4L80E considerably longer than a TH400, which I why I noted that floorpan mods are required. The 700R4 is a new design that is not any stronger than a 200-4R in stock form. Either require expensive mods to live behind a 455. The 200-4R has a BOP bellhousing and is an easier trans to fit in an Olds for other reasons also.

joe_padavano

A reasonable consideration, but note that not everyone is only worried about gas costs. In my case, I want an OD trans so I can run 3.91 or 4.33 gears and not beat up the engine on the freeway.

joe_padavano

The GV may give you access to six different gear ratios, but two of them are worthless. Do you really need an extra gear between first and second or between second and third in a TH400? Do the math on the resulting ratios and effects on performance and you'll find that this sounds impressive but is useless in real life. The OD final drive is the only place that the GV is useful. Real six speed transmissions have a much wider ratio from first to sixth. The GV doesn't change that - first is still the same 2.48:1 of the TH400.

Olds64

You might consider rebuilding the 200-4R yourself if your mechanically handy. That would definitely keep your cost down.

Here's a well rated website that provides high-end transmissions and transmission rebuild parts.

http://www.monstertransmission.com/

lansing

Agree. Seems a shame no one makes just a simple final drive overdrive that would bolt up to a TH400. Maybe for a little less money than the GV unit. Weren't these available many years ago...or is my dementia kicking in again??

joe_padavano

I suspect you are thinking of the Hone overdrive unit, a predecessor to the GV. Both are simple planetary gear sets derived from the Volvo factory overdrive.

lansing

Thanks for the memory jog. Looks like they are making them again, at least for the 9" Ford rear end.
Check out this link for a little laugh.. http://hone-o-drive.com/shop/
Cheaper than GV?...aaaahhhhh no!!!

joe_padavano

Interesting. I was not aware that they were still (or again) in business. Those are purpose-designed to bolt to a Ford 9" to make it a two speed axle. The one I'm thinking of was a divorced unit that went behind the trans.

11971four4two

Agreed that what he / original poster is after final drive ratio...
Have you ridden in a car with G/V whose driver wants to shift 5 times and like it????
"Priceless"
Smiles per gallon

zeeke

Welcome aboard.

I know 69' 442 started saying it but this is a 71' 442 convertible, I'm assuming #'s matching, why mod this car? How much fuel will you save with a 200-4R vs. depreciation? However, if you do mod it make sure you hold the 400. If you really want to get fuel economy keep the secondaries closed.

Steve Sabatini

Hi, I have done 200R4 twice. in my, 71 455 VC and 70 350 vc. Both daily drivers. Engines stock, both transmissions fresh rebuilds with minor + parts (not really needed), all driven smartly, not raced. Only required mods include,
1) Driveshafts need need shortning,
2)trans mount needs relocation to preexisting secondary factory location,
3)TV cable,
4)OD lock up switch- I used a simple rocker.
I did it `cause I just wanted more relaxed cruise, even around town. Definitely worth it to me.
Only down side is, a bit crisper (bordering on harsh) 1,2,3 shifting.

BangScreech4-4-2

Good point -- anybody who's using a car like this as a daily driver obviously has priorities other than fuel economy, anyway.

Carshinebob

My solution on the 71 442 convertible I owned many years ago was to change the rear end. Although My car had a non stock 3.55 in it when I got it. It was fun until the speed limit was raised to 70 from 55. I had a 2.73 laying around, so in it went. It made driving on the highway very nice. It changed the personality of the car but would still chirp the tires shifting to second. The surprise was that the quarter mile et was almost the same, but the trap speed and 60 ft. time changed a lot. probably a good example of how much low end torque can move a car even with a highway gear. So here's my recomondation. Finding a used 2.73 complete rear end wouldn't cost much and you could keep the original to maintain the value of your car. ~BOB