Welcome to Hotrodders.

I moved your new question from a very old thread you posted to.

New thread for answers to your question. Thanks

 

That is a really open ended question. Just exactly do you want out of your Nova? I have a S10 w/ls and 700R4 and 3:42 rear end and would never go back to a 350 T. I love the OD but I also had my trans beefed up to handle it.

 

As a gearbox guy; I deal daily with people swapping out transmissions. I know it might seem strange, but its all about your rear axle and tire combo for me.

If you already have 3.08s and medium height tires, you probably very rarely, if ever, use overdrive; BUT the deep 3:1 1st gear in the 700r4 makes the car very lively to drive.

Most likely, whoever built your car; did so with an eye towards using the OD; which means you probably have at LEAST a 3.42, up to something like a 4.11 rear axle. This coupled with the 3:1 1st makes the car VERY aggressive when you want, but dump it in overdrive and tool down the road nice and easy.

If you go to a T-350, you're going to lose some of the launch, but you'll have less engine RPM drop between 1st and 2nd, which might actually be more consistent on the strip (this depends on a lot of factors and isn't really a consideration for anything other than a dedicated race car).

If you go to a T-350, you're going to lose the overdrive entirely. Maybe not a problem if you have 3.23s or 3.08s in the axle; but you probably don't.

The only way I'd put a T-350 in my car by choice:
all out racing (and I'd probably go to a T-400 if it was drag racing)
its in a T-bucket and I only need a 3.36 rear with 29" tall tires
i'm broke as a joke, and I have a T-350 with a fresh rebuild
i'm replacing a powerglide in a street car, and have a fresh T-350

Just my opinions.
**Edit**
If you want to know what its like, just drive down the highway in 3rd gear for awhile. 3rd in a 700r4 is the same (direct drive) as the Turbo 350.

 

As Indian says, it really depends on what your intended use of the vehicle is, how much horsepower/torque the engine produces, how much time you spend driving on the freeway, what your average cruise speed is, what size tires you have on the rear, and what gears you have in the rear differential.

I don't really care for the 700r4's. So, unless you are doing a lot of freeway driving where you would need the lower RPM's of cruising at freeway speeds, I'd say go to a TH-350. They are much stronger units in EVERY aspect. They just do not have O/D.

If your car is already set up with a 700R4 keep in mind that if you want to switch to a TH-350 you will need a TH350 with a 9" extension housing. Otherwise, you have to get a longer driveshaft if you go with a 6" tail/extension housing.

 

Need more info. What kind of motor. What rear gear ratio in rear. You do know if you go to a t-350 you are going to have to change drive shaft to a longer one.

 

I just bought the car about 4 months ago, i have no idea on the rear end, it's an automatic transmission, but I don't seem to have any power, it has a 350 with a 4 bbl carb. and headers on it. I had a 76 Nova with a 305, 4 bbl carb. stock exhaust and a metric tranny and it had alot more power to it. I just want to press on the gas and go like i did in my 76

 

A 350 and a 4bbl can be a dog, GM made a lot of them back in the first generation of the SMOG era. There are many versions that couldn't run with even a moderately built 305. So you need to look at the 350 deeper. Start by getting the casting numbers on the block and heads. Add to that the engine code stamped on a pad just ahead of the right (passenger) side head close to the water pump. These will lead us to what the engine is, where it came from and when it was made.


The 700R4 is a modified TH350 it uses a deep low which should make almost anything sudden out of the hole. The other mod is an overdrive around .7 to 1 these are pretty gutless in 4th especially if the car has a high ratio rear end which GM is given to use in vehicles before 1986. The other thing is the 700R4 uses a lockup converter, if this has it and it is wired, who knows considering the car has been molested. The lock up is nice when cruising in 4th but it isn't very strong so it needs protective devices that drop it out when the load on the crankshaft goes up. This can be a vacuum switch which the factory used or an old Ford or Chevy brake light pressure switch screwed into the 4th gear pressure passage. This the factory didn't do but hot rodders will, if the transmission isn't in 4th there is no lock up. Since any heavy load will cause it to down shift out of 4th you protect the TCC clutch from overloading. The 700R4 has several issues that lead to premature wear the most common is incorrect TV cable adjustment which leads to lower than correct oil pressures which leads to excess wear especially on the 3 to 4 clutch. So being the beast it is you would have no idea of the transmissions internal condition.


So you've got some research to do before we start changing things to find out what you've really got.


Bogie

 

Plus i can't find a flywheel cover for it, the bolt patterns are dif on the motor and the tranny

 

Are you SURE you have a 700r4?
If your 700r4 with a 3.00 1st gear takes off like a slug, you have something else amiss (wrong torque converter, terrible rear axle ratio - 2.73s or similar).

 

Had a 70 nova years and years ago. If they put a 700 4r tranny into it without lowering the rear gears and used a stock torque convertor, it will run like it dragging a anchor. It will need at least 3.42 rear gear(or lower) and a 2200-2500 stall convertor.

 

The ppl i bought the car gave me a receipt for a rebuilt 700r4, plus the transmission shop said it was a 700r4, i bought a cover for a 700r4, but the guy at the shop said it wouldn't fit

 

There's a few small differences on these transmissions as to how the bottom cover fits. I've been at modify as needed with these things for a long time.


Bogie

 

This is my baby, Novas are my favorite cars

 

Just for your info. Search and find out what it originally came with for a motor. You can find out the rear end ratio was by decoding the numbers on the right rear axle housing . Mine had the 307. that way you will know, when people ask, and they will. Looks good.

 

X2 with this. Other than if this car (or rear axle) has spent much time in the salty north country. Trying to read casting numbers if this is the case is a might bit demanding. And there is also an excellent chance that your 47 yr old car doesn't have the original gears as well. Pulling the cover and getting the numbers off from the ring gear is a pretty easy task that will cost you a couple of quarts of gear oil, a gasket and an hour or two. It will also help you identify exactly what differential you have.


Regarding your low power/sluggish performance complaint, a gear swap is cheaper than a tranny swap IMO. Even if you have to pay someone to do it. New gears and a bearing kit are much cheaper when you combine the cost of the transmission, TC and driveline work.

Once you get it geared properly, then is the time to see if your TC is functional for your application. And to see if the motor output is acceptable. Basically I'm agreeing with several others that the 700's deep 1st gear is going to alleviate more of the sluggish feeling than a T350. I'll predict putting in the T350 will seem like a step backwards when taking off (it will be disappointing) and then you also will lose the highway driving advantages of the 700's OD.

Nice car BTW and good luck.

 

Thanx 2 all 4 the info, much appreciated, my hubby and I looked @ the letters on the differential and from what we could gather is it came off a ford, the ppl who had the car b-4 me really screwed up my car, they lowered the front and rear 11/2 ins, then they put over sized tires on it, which made all 4 tires rub on the fender wells, i finally got that all fixed, the truck leaked cause they bondoed the rear on, had 2 fix that 2, now im trying 2 get a little more power out or it, should i put in a bigger differential?

 

Since you say it is a Ford rear, is it a 9" or an 8.8"??

What rear gear ratio is currently in it??

Either one is far stronger than the stock rear axle was in your Nova unless your Nova was a Super Sport originally.

 

I think it's a 9", but won't swear 2 it, yes it is a Super Sport, is it the bigger the inches the more power?

 

Just found the markings on the gear box, K269

 

That doesn't really tell us anything. Ford rear axle I.D. is a small metal tag with a stamped code held on by one of the cover bolts or centersection nuts

Does it have a rear cover, held on by 10-bolts.....or does the entire center section drop out of the front of the axle housing after removing 10 nuts??

A true Super Sport would have had a 12-bolt Chevy rear axle, any idea why it was removed?? Because it was plenty strong enough, there would be no need to change it.

 

The ppl who had it b-4 seemed 2 try and make it in2 a hotrod, but didn't no how 2 go about it, the motor has a serpentine belt, u no as well as me they had 3 belts originally on it

 

This is most of what I have

 

Dam someone put a lot of goodies and money in that Nova and it's pretty funny reading some of the things they were charged for, LOL.....
Car looks clean and in very nice condition :thumbup:

Sounds like the whole car has been gone through; suspension, fuel system, mechanical & electronic fixes, drive shaft, motor, trans, and....

Unfortunately your still stuck only knowing you have some kind of rebuilt 350 and a 700R4, but you still have no info on the motor, convertor, rear & gearing. The wrong cam, heads, gears, or convertor, can turn any car into a slug very easily. Then again something as simple as the wrong timing and tuning can do that also so there are just so many unknowns here. Do you have any friends with good car knowledge that can give it a good look over?

Do you have any good pics of the motor, the heads, the rear, can you get some engine numbers off it and post them ?

Here's my former 72, I miss it and I'm constantly looking for another...

 

I see why they call him 'Pro Street Rob' lol

 

You kidding, that looks like a mileage getting grocery getter :l .

Rob, why did you sell it:spank: That's a beautiful car.

 

Sweet ride u had, when it quits raining here I'll get some more pics

 

I know its a sickness, but thank god there is no cure.