[glhs#116]

As someone who has driven 5 speeds until now I gotta say I'm hating my TH350 and 3.42 gears on my 71 TA. Thing I hate more than the constant rpms are the way if I get into a race on the highway I'm out of breath after not too long and there just isn't another gear. My motor has torque and I just know it would stomp all over these little buzzbombs if only it had another gear for high speed. I'm a bit of a speed case so I really miss being able to use the power when already on the highway. I've got a 3.08 ring and pinion. I'm really hoping that makes things a bit better once I get around to swapping it.

Sam

[Silver Judge]

Originally Posted by glhs#116

As someone who has driven 5 speeds until now I gotta say I'm hating my TH350 and 3.42 gears on my 71 TA. Thing I hate more than the constant rpms are the way if I get into a race on the highway I'm out of breath after not too long and there just isn't another gear. My motor has torque and I just know it would stomp all over these little buzzbombs if only it had another gear for high speed. I'm a bit of a speed case so I really miss being able to use the power when already on the highway. I've got a 3.08 ring and pinion. I'm really hoping that makes things a bit better once I get around to swapping it.

Sam

I hear you on that one ! I have 3:55 gears and a 4 speed and I constantly wish I had a 5th Gear to BANG ! If and when I get a 5-speed, I'll probably wish I had a 6th gear to hit too. What's next? A 7-speed

[Junkyard Dog]

Originally Posted by glhs#116

As someone who has driven 5 speeds until now I gotta say I'm hating my TH350 and 3.42 gears on my 71 TA. Thing I hate more than the constant rpms are the way if I get into a race on the highway I'm out of breath after not too long and there just isn't another gear. My motor has torque and I just know it would stomp all over these little buzzbombs if only it had another gear for high speed. I'm a bit of a speed case so I really miss being able to use the power when already on the highway. I've got a 3.08 ring and pinion. I'm really hoping that makes things a bit better once I get around to swapping it.

Sam

Hmmm . . . With my aforementioned 3.73 gear, I touched 145 before backing down due to rpm. This was with a 27 inch tire. That ought to be enough velocity outside of a racetrack for even a speed case . . .

[Formulabruce]

heres where my 200 came from, nice support too. mine is stage 3 raptor (500hp rated)
youll need to get the cable adjustment precise on either. the 200 was used on buick,and olds engines and bolts right up to a poncho. should be a bolt in for the 68, same driveshaft as powerglide or standard. might need a diff crossmemeber, but tranny is same length as a th 400. http://www.transmissioncenter.net/200-4R.htm

heres one of mine on a 455

[Tom Vaught]

Quote:

"I put 4.10's in my 6-speed '94 Z28 and still turn barely 2000 RPM's @ 70 MPH. I drive my '70 Judge with 3.55's, and even around town at 45-50 MPH, I still instinctively attempt to shift it out of 4th into a non-existant 5th. Can't believe we used to consider this a compromise gear. A RA IV w/4.33's would be near insane on the highway."

I ran a 4.33 gear set in college with a 4 speed for 4 years, course gas was relatively cheap and I did not have far to go to get to the bar! I took the car on a 150 mile trip one time and burned the full tank going the distance. About 7 mpg, taking it easy. With today's gas prices that trip would have cost me $60.00 a few weeks ago.

Today I have a Ford 9" rear under the car with a 2.75 gear that will work with a Nash 4+1 Five speed trans. The engine will be a 455 E head deal. I think it will have plenty of torque to pull the 2.75 gears on the road.

Tom V.

[cblandin]

Another downer to extended high rpm cruising in my 455 powered vehicle has been heat. Living in Dallas, where it is still over 90 degrees at 10:00PM in the Summer, presents some problems with that heat generating beast at those kinds of rpms. The temps slowly begin to creep up. Yeah, I know I could do the better radiator, fan, water pump bit (note: I have astock 4 core radiator, new HD fan clutch, 7 blade fan, and water pump with divider plate clearanced), but these things still generate some heat and at 3500 rpm there's just that much more of it. When I look at the responses to this post it seems like most folks are lined up with me. We aren't old (OK, not THAT old) - we just appreciate what overdrives have been bringing to the table for over 20 years now. They really do allow you to have your cake (low gears for great acceleration) and eat it too (i.e. great highway cruising)...with the exception of some strength and cost issues of course (oh dang, there's the catch). I know it isn't easy dole out $1000-$1500 (sometimes more) for a high strength overdrive automatic, but a lot of us are dropping that much on heads, and other performance goodies just to make out cars more powerful (translation: ENJOYABLE) - so doing so for an extra gear isn't really that big of a stretch. As an aside, I swapped out a Turbo 350 from my 82 Firebird (origincally equipped with a 200C), and put in a 700R4 (with 3.23 gears) - behind a stroker 383. I loved that swap, but not for the mileage improvements (which never seemed to materialize) - for the driving enjoyment as I noted earlier. I just finished rebuilding the engine on my Bird and am not yet ready to drive it to any great degree so I'm holding off on swapping out my TH400. I may even try a taller tire first, but ultimately I'm going to do something if I drive it more than a little to bring those rpms down (a TKO 600 would be my ultimate choice, but we all have a budget).

[ChrisTransAm78]

I have 3.55's in mine w/ a 9" w/ a Tremec 5spd - runs about 2 grand. Diff tranny and its a stick but...Man I love it! I drive a hotrod...others are expecting it to sound like one...the more the merrier in my book!

[67 455 Bird ragtop]

This topic is one reason I have 9" in my 67 'Bird. I plan on three sections. The current 3.55's for daily around town driving, 3,89/4.10 for the strip, and a low 3 or high two for extended highway cruising. Of course this is the plan for now. Time will tell how it works out.

Still haven't totally given up on a 200 down the road. But for now I'll stick with my TH400.

[MRGTO2U]

As I read all the reply's for this post I concluded that the 3.55 or any other rear gear people have has to suit what the person intends to do with the car. Example: In January, I purchased a 68 GTO with a 428. TH400 and mildly modified on eBay. Well, my great looking GTO that had a 7 liter engine and sounded awsome, was actually a dog accelerating because the previous owner installed a 2.78 open rear. Ok, great for the highway doing 60 at 2500 RPM but I wanted a classic Muscle car with some huevos (balls)! Kids with 4 cylinder imports and my wifes 98 Lincoln Continental could outrun me from Light to Light. Hey, I didn't want a slow Muscle Car, So I talked to a local mechanic who is into high performance and he recommended the 3.55 gear with a posi unit. OH MY GOD WHAT A CHANGE!!! The car is so much fun now, It will burn rubber al through first and second gear if I don't take my foot off the pedal. Conclusion, My daily driver whether it be the Nissan Maxima or the Lincoln cruise at 80MPH at only 2200 RPM which is great for normal daily drivers but my classic GTO had to be a Muscle Car with an attitude.
I don't know what other's will respond but it comes down to what you want the car to do.

Take care all!!!!

[tjdjr]

I run 3.36 and it's not bad on the highway. I do notice a big differnce in gas mileage I had 2.56 and changed to an Eaton posi and 3.36 gears. If people want to pass let them, but as they go by they'll be looking at your car !!

[glhs#116]

Man, if I weren't stuck in this one camel town for the moment I'd be running, not walking, to the nearest place that could stuff a TKO in this bird. I think this car would be an absolute animal with gears I can shift myself, lower lows, and higher highs. I just can't see a downside. It's the thing I most want to do to this car.

Sam

[Barrier Blue]

Originally Posted by 6t7gto

60over,
i took 3.55 out of my car and went with 2.56.
cruise the highway at 2200 rpm now.
check this out...
http://www.tciauto.com/tech_info/calculators.htm#7

david

Must be one of those '67 Lemans rear-ends.

[KS circutguy]

I am told these are the answer for T-350- T 400 trans.
Tom, any experience with the durability of these units?
http://www.gearvendors.com/hrgm3s.html

[uneasyrider]

Originally Posted by TR

You've nailed it down dead-on. Time was, 3.55's were once universally considered an all-around good compromise between highway cruising and max acceleration. A good gear that a musclecar owner can live with in daily life.

Fast forward to having owned OD equipped cars since '85. Having our cake and eating it too. I put 4.10's in my 6-speed '94 Z28 and still turn barely 2000 RPM's @ 70 MPH. I drive my '70 Judge with 3.55's, and even around town at 45-50 MPH, I still instinctively attempt to shift it out of 4th into a non-existant 5th. Can't believe we used to consider this a compromise gear. A RA IV w/4.33's would be near insane on the highway.

LOL! Yep, I've looked for that "5th gear" before too. I would agree with the above and add that I have a close ratio 4spd and 2.73's in my '74 TA and I like the combo generally. Better would be a 5spd with an od 5th and 3.55's BUT I didn't have the cash for the 5spd. I turn about 2,300 on the highway at 70mph and it sure helps the mileage. I have a healthy 462 in it and it's getting 19mpg on the highway if I haven't got my foot in it and that's the hard part. The only thing I don't like about it is reverse in tight parking spots because reverse uses 2nd and it loads up if you have to do much backing or there is a hill etc.

[tom s]

I have 3.55s in both my 69 RA V T/A and GTO.That IMO is as low as you would like in a steet car.I drive to a lot of shows that are 30-50 miles away and usually in the slow lane at 2800 RPMs.My 421 lemans has the tremic with 3.90s and is very drivable on the freeways.Tom

[Junkyard Dog]

So, Tom, you would recommend 3.90 with the Tremec? What does that do to your first gear? Doesn't the Tremec have a really low first gear comperd to the Muncie M-22?

[gearbanger]

The TREMEC has a 2.87 compared to the 2.52 in a muncie. I have 3.55 with a 27 inch tire and I am going to 3.73s so that I will keep exactly the same gearing with the 28.4" tires I am switching to. I think the gearing is perfect right now with my 461. Mine is a TKO 600, the 500 has a really low 1st, 3.27 I think. IMO that would be way to low for the torque of the 461.

[tom s]

actually the 3.90s are too tall for my combo.The 4.56s were great but with the 3.27 first gear I was getting no pull in first.Im putting in a 4.30 in the next few weeks.If I was to do it over,I would opt for the TKO 600 with the taller first gear,a 4.30-4.56 rear and the .67OD.Remember,4.56s with the TKO is like 3.08s in 5th.My cam really does not allow me to drive in 5th gear under 2000RPMs.Tom

[gearbanger]

tom s, you must never drive your car on the interstate. With 4.30 or 4.56 gears you would be cranking up around 2800-3000 rpm wouldn't you at say 75 mph. I personally wanted to take advantage of the overdrive from interstate cruising and otherwise have the same gearing as I always did with the 4-speed. In other words I am gearing mine to only use 4 gears in a quarter and not use 5th. Do you feel that you are getting quicker 1/4 mile times by using all 5 gears? What size engine do you have and what hp and torque?

[tom s]

I dont use all 5 gears at the track.My car with 4.56s goes through the 1/4 at around 6000.That is where I wanted it to be.It gets 17 MPG with freeway driving at around 2600RPMs.With my engine combo it has been almost perfect.I think the 4.30s I just got will be right on and if I chose to put in a TKO 600 with the taller first gear the car will 60ft much better.The car runs 112 at 12.20s with 1.70 60 fts.And your right,I dont drive this car at 75MPH on the freeway no matter what gear I have in it.Tom