andylmusic76

i don't lik my car revvin' above 3500 down the interstate or when i'm cruisin' in the county. i've really been debating whether or not i should put like a US Gear or GearVendors overdrive unit on the Turbo 400 or just swap the tranny out...I would probably go with a manual though unless anyone knows of any great automatics...

here's where the dilemma is: the overdrive can be upwards of $2200, and a rebuilt tranny could be bought for much less...

69427

What sort of driving do you do with this car? Is changing the rear gears an option for you? It's a lot cheaper.

andylmusic76

i have thought about doing that...actually if anything i would go higher than a 3.73 which is what i have now for better acceleration...i guess i just want the best of both worlds that's why i would keep a 3.73 or go up, but then have the overdrive gear (~.92:1 something like that) for cruising. my '77's my daily driver, so i want it to be more on the economical side (yeah, like that's possible ), but i want to catch the attention of mustang drivers once in a while

kona

I did my OD 200r4 swap for alittle less than $1,600 and that was with a shop doing all the labor.
Shop around might not be as much as you think.

Kona

Gordonm

Keep the gears and get the overdrive trans. You will be happy and the cost is not as bad as you think.

Big2Bird

kaiserbud

That is what I plan on doing (if I ever get enough $$$) and I have the 373 too !

Retro78

Change that Trany and keep your gears. I went right from a 350TH to a T5-standard at Norval encouragement. Bang for the buck....very high. All I can say is ...it is a very different car now.

Shirley1978

this might be way out of your budget but when i swaped my automatic to a TKO-600 from keisler i didnt recognize the car... it was sooooooo much better it was a butt load of money but in my opinion itle pay for itself in gas with todays prices..(might take a while though )

i have zero regrets
jonny

BerniesVette

Like Carguy4sure, I installed a mustang T5 manual 5 speed in my 79 that had the 350 auto. it became a different car that performed better, ran cooler and went from 16 to 20 + MPG on the highway. My swap cost less than $1,500.00 with me doing the work. I would do it again in a heartbeat.
If you want to stay auto, the 2004R is the easiest swap and will serve you well too!
Bernie

BerniesVette

Like Carguy4sure, I installed a mustang T5 manual 5 speed in my 79 that had the 350 auto. it became a different car that performed better, ran cooler and went from 16 to 20 + MPG on the highway. My swap cost less than $1,500.00 with me doing the work. I would do it again in a heartbeat.
If you want to stay auto, the 2004R is the easiest swap and will serve you well too!
Bernie

shafrs3

I don't think a GearVendor's OD unit would fit without some major hacking.

mrvette

I understand it will, but for the lousey 20% engine speed reduction, i'ts not worth the money/time/effort.....it's only a .8 overdrive.... .7 something is much better.... but if it was me, id' make it .5 or .6 .....

jerrylee

My car has the 700r4 tranny n she cruises around 2000 n she still has plenty of punch off the line suprisingly with the original 3:08's in her...if u are going 2 get rid of the 3:73's give me a hollar....Jerrylee///

Crash80

Yep, you have to really cut on the tranny tunnel and drive shaft to get it to fit. That fact, along with the cost would keep me from doing it.

markdtn

I have a 700R4 and 3.7 gears. first gear is useless. I would recommend 3.36 or even 3.08 with a 700R4. That would be the best of both worlds.

kaiserbud

Markdtn - 1st is useless? - can you give more info?

Crash80 - hmmm - I didn''t realize that.

Gordonm

Depending on your motor combo the 3.08 gears with an OD trans will put your cruising rpm to low. If your cam is a low end cam with little duration you might get away with it. My cam will not run worth a crap below 2000 rpm. If I put 3.08s in my car I would have to be doing 80+ to be able to use 5th gear. You cannot just plug in an OD trans without knowing the rest of the combo. My 1st gear goes up in smoke also but on the strip with traction it is great. I'm only in 1st a short while. 2nd gear is pretty tough also when you have a lot of power.

Big2Bird

Trust me. I put in 3.08 while I had the TH-350C. Changed to 700-R, and cruise 65 about 1900RPM. I am going to change gears again to 3.55 or 3.73.

Fevre

Got a 700r4 and 3.73 on my Formula and agree 1st gear is too tall, anything over 1/4 throttle and the tires are like the Cheech and Chong movie 'Up in Smoke'