Author Topic: TH-350 vs. 700r4  (Read 3312 times)

Andy005321

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TH-350 vs. 700r4
« on: March 10, 2015, 05:33:09 PM »
I was planning on building my high performance 400 for a BW Super T-10, but am tossing around the idea of installing a TH350 instead...since the car is designed for an auto trans. It would be cheaper, that's for sure, but I'm looking for someone to either talk me out of going automatic, or explain why it's going to be better in the long run.

A) Auto vs. Manual in a performance Trans Am?
B) TH 350 vs. 700r4 in a 79 Trans Am?
Bleeding knuckles, torn open hands, oil in your mouth, grease on your face, music blasting, ratchet in hand, Trans Am above you....You're underneath the greatest car in the God darn world and there's nowhere else you'd rather be!!

GAbandit

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Re: TH-350 vs. 700r4
« Reply #1 on: March 10, 2015, 06:03:41 PM »
I'm kind of biased because i just recently bought a 4 speed pull out and plan to put that on mine, but if you are dead set on an auto the 200r4 or 700r4 would be way better than a TH-350 from what I heard, simply because the r4s are a 4 speed auto vs the TH being a 3 speed. Personally I would pick the manual because to me I think a manual would be a lot cooler with a high performance engine. If you do decide to go with the TH-350 or an auto in general I could sell you the parts from mine that in pulling out, pm me if interested, thanks.
1978 blue T/A sold
1978 black T/A- Project (Chicken coop find)

Box

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Re: TH-350 vs. 700r4
« Reply #2 on: March 10, 2015, 06:46:01 PM »
They're called auto-tragics for a reason, the only reason I settled was even if I bought an original 4-speed car I'd still be modifying for a hydraulic clutch and overdrive trans.  If going with an automatic go with the 200-4R as it's a direct replacement for the TH-350, as the 700-R4 requires a shorter drive-shaft.

1996 Pontiac Firebird Formula hardtop 6-speed

Grand73Am

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Re: TH-350 vs. 700r4
« Reply #3 on: March 10, 2015, 07:09:26 PM »
Not only does the 700r4 require driveshaft shortening, but also an adapter plate to be able to bolt it to your Pontiac engine, due to the different bolt pattern. 200-4r doesn't require the adapter plate.

For the automatic, it depends on if you want or need overdrive or not. A th350 is simpler and cheaper and strong enough, but no overdrive. It would be at comfortable rpm's if you're running 3.23's or numerically lower rear end gear ratios. I'd go with 2.73 or 3.08 for lower rpm highway cruising.

Also remember if you went with a 4 speed manual, you won't have overdrive either, and you'd want to use at least 3.23's.

If you're running 3.42's or more, then an overdrive automatic, or manual with overdrive, would be preferable in my opinion.

 
Steve F.

scarebird

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Re: TH-350 vs. 700r4
« Reply #4 on: March 10, 2015, 07:22:46 PM »
Quote from: Grand73Am link=topic=69601.msg646055#msg646055 date=1426036166[color=yellow
Not only does the 700r4 require driveshaft shortening, but also an adapter plate to be able to bolt it to your Pontiac engine, due to the different bolt pattern. 200-4r doesn't require the adapter plate.

For the automatic, it depends on if you want or need overdrive or not. A th350 is simpler and cheaper and strong enough, but no overdrive. It would be at comfortable rpm's if you're running 3.23's or numerically lower rear end gear ratios. I'd go with 2.73 or 3.08 for lower rpm highway cruising.

Also remember if you went with a 4 speed manual, you won't have overdrive either, and you'd want to use at least 3.23's. [/color]

If you're running 3.42's or more, then an overdrive automatic, or manual with overdrive, would be preferable in my opinion.

I had a TH200-4R behind a 462; you will want 3.55' or 3.73's - 3.23's too steep for carbed non-computer engines.

Re: TH-350 vs. 700r4
« Reply #4 on: March 10, 2015, 07:22:46 PM »

h3bubba

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Re: TH-350 vs. 700r4
« Reply #5 on: March 11, 2015, 07:15:34 AM »
I'm running a 200-4R behind a 470 HP 400 with alum heads and 3.42 rear gears without issue.  It also has a lock up torque converter for even lower RPM while cruising on the HWY.  It is hooked to a vacuum switch that unlocks when I step on the gas a little to get the engine back in the power band for acceleration without having to downshift.  I love it.  Especially here where traffic is horrible at times.  I agree that a hydraulic modern set up for the clutch with a 5 speed would be the best set up though.  Eventually I will get there, but I am having a great time with the 200.  the 700 was set up with a much lower first gear for use in trucks.  This helped them get off the line a little easier when pulling a load.  The 200-R4 was original equipment in the Buick Grand National and the 1989 Pontiac Turbo Trans Am.  As mentioned above, the swap was easy as well.  The only mods I had to do was to flip the cross member around and drill some holes to install it. 

Setting up the TV cable is something you will need to research extensively so you understand it.  It's not magic or hard to understand, but getting it wrong can screw things up in a hurry.  PM me if you have any other questions on the install. 

1979 Pontiac Trans Am WS4
1975 YT 400,  0.030" over, KRE D-port heads
200-4R, Stage 3
Complete Gen II(PTFB) Front/Rear COMP suspension package
10 bolt w/Moser Street axles, 3.42:1
Bear T4 13" front and SS4 12" rear disk brakes
275/35R18 (18x9) front, 295/35R18(18x10) rear
FITECH Meanstreet EFI

1979 TATA 400/4spd restoration next...

ILLTA77

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Re: TH-350 vs. 700r4
« Reply #6 on: March 11, 2015, 09:06:37 AM »
The adaptor plate for the 700r4 and shorting the drive shaft are no big deal.   The 700R4 has a lower 1st gear ratio than the 200R4.    I would not go with a THM350 if you don' have one already, the overdive will help keep the rpm's down at higher speeds (Tollway). Either transmission can be made to handle the horsepower.

I have a 455 with a 700R4..   
« Last Edit: March 11, 2015, 01:58:57 PM by ILLTA77 »

oldskool

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Re: TH-350 vs. 700r4
« Reply #7 on: March 11, 2015, 10:02:13 AM »
Unless your car is a daily driver, high speed  freeway cruiser, I'd go with a TH350, especially if you ever plan to try any bracket racing at the strip. To me, snatchin on a 4-speed is really more fun on the street. But a properly built HD TH350, will work much better at the strip. And, to get in a little more shifting, you can install a ratchet shifter.

You can match your stall converter and rear gear to the kind of driving you'll be doing. Just the TV cable deal is enuff to scare me away from one of the 4-speed autos. BUT, the high speed cruising ability and better gas mileage is the main consideration for some. So, for these guys, an OD of some sort is the best choice.  :-)

Chuckles

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Re: TH-350 vs. 700r4
« Reply #8 on: March 11, 2015, 11:38:04 AM »
Me personally? I tend to advise against 700s/4L60s. For the sheer fact they're not a very heavy duty/reliable trans. The torque of a performance Pontiac will shred it. TH350/400/4L80E is only kinda of automatic I'd run.

Phil G.

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Re: TH-350 vs. 700r4
« Reply #9 on: March 11, 2015, 12:09:21 PM »
One vote here for the 700R4.  Best upgrade I have made to my car.  I purchased mine with an adapter plate and custom torque converter from Phoenix Transmissions; they custom build it to handle different power levels.  My only complaint is that they have the governor set at 5,500 rpm and my motor pulls to 6,200 (I have a highly modified Oldsmobile small block in my TATA that is pushing out over 475hp at the crank).  So I have to manually shift for maximum thrust.

If you go this route, I would recommend you go the extra expense for a custom driveshaft (billet) rather than use a shortened factory piece - I was getting terrible vibrations (above 120 mph).  The best part is at 70 on the highway I'm turning about 2,100 rpms with 3.42 gears.  And that low first gear is great.

I know a lot of folks on this site swear by the 200r4 but the 700r4 is stronger (but heavier).

http://webrodder.com/article/700r4-vs-200r4-which-is-best


Phil G.

1979 TATA w/built Olds 375/700R4
1979 Nocturne Blue 403/Auto
1985 Toyota Supra
2011 Harley Davidson XR1200X

ILLTA77

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Re: TH-350 vs. 700r4
« Reply #10 on: March 11, 2015, 02:01:01 PM »
Nice article ....  Good photos with a side by side comparison.  With good infomation, the owner can make thier own informed decision.
« Last Edit: March 11, 2015, 02:03:58 PM by ILLTA77 »

tajoe

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Re: TH-350 vs. 700r4
« Reply #11 on: March 11, 2015, 02:23:39 PM »
I was planning on building my high performance 400 for a BW Super T-10, but am tossing around the idea of installing a TH350 instead...since the car is designed for an auto trans. It would be cheaper, that's for sure, but I'm looking for someone to either talk me out of going automatic, or explain why it's going to be better in the long run.

A) Auto vs. Manual in a performance Trans Am?
B) TH 350 vs. 700r4 in a 79 Trans Am?

 What eng. is in your car, and how much HP (Pont., LS,?)
 How do you plan on driving it. (Street, Street/strip, Drags, Freeway brawler, cruise nites only, DD?)
 Will left foot illiterate drivers also need to drive it?
 How much cash and work do you want to spend?

 My preference? All performance vehicles should have 3 pedals, but I'm old school, and that's just me. :?
 
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800qjet

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Re: TH-350 vs. 700r4
« Reply #12 on: March 11, 2015, 03:54:34 PM »
On a pure street car with a built engine, that is not going on long trips, that needs a durable trans to take the pounding - I vote for a built TH350 or TH400 (with the 455+ engines.  Match the cam, torque convertor and rear gears, as well as other things like the exhaust, timing.  The money spent and the complications are less also.  X2 with oldskool.  The way I look at mt car is the way I look at some of my rifles - can you throw it out the window, pick it up and shoot it a long time with no problems (military type rifles).  Sometime the gadgets look good in the ads and articles but they don't always help.
You can tell a lot about a woman's mood just by her hands. For instance - if she's holding a gun, she's probably angry.

tajoe

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Re: TH-350 vs. 700r4
« Reply #13 on: March 11, 2015, 04:01:57 PM »
X2 on the above criteria, if you need to run an auto.
"You can sell an old man a young mans car,
but you can't sell a young man an old mans car"
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Re: TH-350 vs. 700r4
« Reply #13 on: March 11, 2015, 04:01:57 PM »
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