when I remove my LG4 and 700r4 and put in 350/TH350 ???

that 350 is also carbed so I am assuming that I can reuse all the carb/throttle linkage , right ?

but , what about the computer ??? the car that I got the 350/350 combo from did not have the ECM anymore. So , what do I do ?

can I disconnect the ECM and that's it ? I realize that I won't be able to check for "Error" codes anymore since the ECM won't be there , but will all the gauges work ok without the ECM ? (I have a TA , so will the speedo/tach/water temp/oil press/battery voltage and fuel gauge still work ?

also , can I reuse my sensors from the LG4 ? (since I Know they are ok and will last a while , I've had the 350 running for a while , but not more than 5 minutes and I was unable to drive the car so I don't know if every sensor is in good shape...

can I reuse my stock shifter from the 700r4 and use it with the TH350 ? he had a B&M shifter installed and I hate the way it looks , shifts and rattles... (by the way , it's for sale , check out http://doudleby.fbody.com )

So without the ECM will everything still work ? (I Guess it's a stupid question ,but I have no clue what ECM controls and what it doesn't).

this swap will be a huge headache since it's the first time I'm doing this , but hopefully with your help I'll get through it ok

Can I use my old driveshaft or do I have to use the one that was in the other car ? (doesn't matter , I still have the parts car , but I want to remove the stuff I'll need and junk the rest before I even attempt the swap , I need extra space so I want to know what parts to save for the swap).

thanks !

 

bttt

 

I am planning to attempt a very similar swap, so let me know how it works out for you

 

guages should be fine, they are on a seperate engine harness.

the sensors should be fine for the dash guages provided that GM did not make any weird changes in that area.

Throttle linkages should be ok.

leave the ECM and all of its harness out but do not damage it, You may wish to reuse it or sell it.

the shifter should work, may have to mix and match brackets at the trans make sure the detents line-up correctly.

I'm thinking that you will have to use the DS that came with the TH350.

Very important: the computer controls all of the emmissions on the engine, if you eliminate it then you will have to use all the older style peices to get through the inspection. Unless, of course, you do not have as stringent E-checks there in Springfield as we do here in Dallas......




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'84Z28/'92 305TPI
'92 complete rear suspension/PBR disc/Posi/3:42
Light weight 34.5mm stabilizer bar in front
23mm sta. bar in rear
rear lowered 1" by cutting 1 1/4 coils of '84Z28 springs
comp cam, flowmaster
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MAT relocated
Ram-Air(home-made) gutted air-box
IROC ground effects/wheels GY245/50's
700R4 superior shift kit/ corvette servo(excellent shift kit btw)

Rebuilt engine and transplanted it myself.

Love this engine!

freshly painted OCT. 2000 Teal with two white stripes on the hood and deck lid

LOW performance people should drive low performance vehicles!

 

Cica,

What year is you car? The ECM controlled different things in different years. If you have an emissions test, you might need to keep the ECM.

Also, why would you change from a TH700R4 to a TH350? They are essentially the same transmission, except the 700R4 has overdrive. Keeping the original trans would eliminate the driveshaft problem, and the linkage situation. If you have a TCC, youre ECM will need to remain to control that if you still want to use it.

------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

 

thanks guys !

oh and the car has 1985 ECM. (85 TA).

anyway , I am going with the TH350 because my 700r4 is almost dead and getting worse with the LG4 running it , so I am 99% postive that the 350hp engine would tear it apart in a matter of weeks. (I will switch back to 700r4 as soon as I can save enough money to have it rebuild, 'till then TH350 will have to do).

And yes we have emission control here in MA , but no one around here really does it , I know of at least couple shops that don't do it , and as far as I know I can still pass the emissions as long as I have everything running right (carb tuned , new cat etc...). I wouldn't pass the visual inspection , but then again no one around here cares.

 

I did the V6 to V8 swap with the 350/TH350, the TH350 had the long tail shaft, measure the tranny from the top edge to the end of the tranny, should be around 32 inches or the same length as your 700R4. If it's not your gonna need another drive line. You can use your original shifter, it just bolts to the tranny pan using the pan bolts. The bracket is a little short so one end will rest on top of one of the bolts. If you have a welder or know someone who does, you will have to add about a 7/16 inch of metal inbetween one of the holes to make it bolt up correctly. I did have it halfa$$ed resting on top of the other bolt, but that's just not right so I fixed it. Then your gonna have to either buy or make a bracket for the torque arm. Since I'm a welder/fitter and have a torch and welder it was no prob.

------------------
1986 RS Camaro
Mods: Threw 2.8 in garbage, put in rebuilt
350 .060 over, XE268H Comp cam, Edlebrock
Performer Intake and Edlebrock 600 CFM Carb,
Pete Jackson noisy GearDrive (which sounded
cool for about 5 minutes, now I'm sick of it)
Rebuilt TH350, 3.42 slippage in the rear.
Killer Power, OH YEAH!!!!
Gonna blow up that V6 rear real soon

 

I have a question about the comparison between a turbo 350 and a 700R4. I have 2 cars with turbo 350's (73 Laguna and an Olds)that have never experienced a problem with the transmission. I literally don't know anyone who hasn't rebuilt their 700R4 at least once, if not twice (my Blazer's been through 2 now as well). What makes the 700R4's prone to failure? I've thought about retrofitting a 700R4 into my 81Z, but I didn't want the hassle of regular rebuilds.

------------------
Z's r Best

 

Z's,

GMTech is the real transmission guru. My limited understanding is that the TH700-R4 is the same basic design as the TH350, but with overdrive. The 1986 and later 700s have an improved pump and valve body, but improved compared to the old TH350, I don't know. I do know that heat and old oil are the worst enemies of an automatic, so regular oil changes are key to long life.

------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

 

I would have to agree with Z's R Best... I personaly had a 84 Z28 about 6 years ago and it had a 700R4 in it. It of course was a 305 but had all the computer stuff removed. It had headers and that was realy about it. When I got the car the tranny was going out (go figure) so I put a new one in it. Within a year That one was going out also. That is when I got ride of that car. Not because I didn't like it but I could not afford a $1,000 trans rebuild every year. I have had several TH350's in cars that I have raced and driven and have never had one go out on me that was not 20 years old in the first place. I friend of mine builds alot of tranny's and he can not keep a 700R4 in anything for any period of time. He is a very patient person and I know he has rebuilt the 700R4 in his car at least 5 times in the past 3 years (he does have it behind a 400+hp motor) and the TH350 that was in there before was in there for 7 years with a 10" converter driven everyday to and from work and to and from the track and never had a failer. As a matter of fact out of alol the guys I know with 700R4's in there cars there is only 1 that has never had a problem with his. So I am not fond of hte 700's as you might guess. If I had to go with an automatic overdrive tranny it would be a 4L60E or a 4L80E.

Another thing... why are 700's so expencive to rebuild? I can get a fresh rebuilt TH350 for $150 but a 700R4 will run you close to $1,000 why is that? I am not made of money that is why I don't run fuel injection or overdrive.

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82 Z28 with 350.motor has .030 forged flat top pistions other wise stock bottom end, Summit 214/224 cam with 1.6 Harland Sharp roller rockers, stock 882 heads for now (will be getting a set of the 23 degree Trick Flows this summer), Performer RPM intake, Holley 750 Vacuum secondary, Th350 with 2200 converter, stock 3.23 geared rearend for now (getting 9" later on), Headman shorty headers, custom 2.5" into 3.5" Y pipe into M.A.C. offroad pipe and M.A.C. cat back system. So far car has only been to the track twice and is having sever traction problems but is running 60'-2.34 1/8 mile-9.2 @ 79 MPH.

 

TH350 are a dime a dozen, and are real easy to rebuild. Usually when a tech wants to get into transmissions, its the first one they dive into because they are so easy, its a confidence builder. If a new tech dove into a 4T80-E (Cadillac/Olds FWD) the first time, it would be there last!

Everybody has there own opinions on why 700's fail. Usually, I see it from low fluid level/lack of maintnence. I have serviced my tranny regularly, and take it to the strip at least once a month and have 160,000 miles on the tranny, no problems at all (knock on wood). Sometimes you get one built on a Monday or Friday and thats just the luck of the draw. Many say the 3-4 clutches are weak, but its the same 3-4 clutches used in the new vette, F-bods, and trucks.

The 700 in stock form is a good tranny, but if you are really pushing a lot of HP/TQ, than you need one that is built just for that.

Actually, Vader, it was '87 and later. And I'm not really a guru, I just enjoy what I do! (I take my job seriously). I take offense when a ******* cracker trans shop says that there rebuild failed because the V6 that it was put in was "hot rodded" yeah whatever.

As for people who run fuel injection and OD haveing money, can I have some of what your smoking? Please?

------------------
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ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey, 22# injectors,
JET AFPR, Ported Plenum,
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SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
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Flowmaster Exhaust,
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Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

[This message has been edited by GMTech (edited January 01, 2001).]

 

They are similar but they had to reduce the size of some parts to get the O/D inside. However, anybody that doesn't do a good job on the rebuild will have failures. The cost factor is because of complexity of the internals (more labor). BTW there is more to a rebuild than just changing parts. Nowadays transmissions are designed to slide shift you need to reprogram it to make it hold HP.

Hope this makes some since,
Don>>>

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Chronologically challenged. But still alive!
92 CAMARO RS
305 TBI 5/spd (now TPI)
'69 camaro
BB/Lenco
1050 dominators
8.97-150+
Pump gas/no drugs

 

Z's r best,
I agree with GMTech on the longevity thing, my 700 has 211,400 miles on it, I have just taken care of it better than some of my buddies have taken care of theirs. If you keep it serviced and maintained properly it will last a long time.

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1986 IROC "Bone Stock" (for now)

[This message has been edited by wiggy'sIROC (edited January 01, 2001).]

 

The reason for that coment is like I said. The cost differance is huge between building a carbed motor and and injected motor. You can buy an intake a carborator and be done for what you can buy just the intake of an injected motor for then you still have to buy the injectors, throttle body and MAS or MAP depending.. and if you are starting with a carborated car you still have to buy a computer and all the wiring. And of course the lap top to tune it...lol. If you don't see a huge price differance "I would like some of what YOU are smoking!"

I can understand about the tranny's being more to rebuild because of the more complex internals. Also that they need to be built to withstand a perfomance motor because they were not originaly intended for that kind of use. The ones that my friend has built he has used various differant kits (B&M, Trans Go, TCI..etc)but has had problems with every one so far. Don't get me wrong, they drive fine but when it is hammer time they die young. The only differance between his and the one guys that has had no problems (his is behind another 400hp motor)is that the guy with no problems does not try and keep it floored into overdrive and everyone else does. Theres all fail quickly and his has lived for close to 4 years now with out a single problem.

------------------
82 Z28 with 350.motor has .030 forged flat top pistions other wise stock bottom end, Summit 214/224 cam with 1.6 Harland Sharp roller rockers, stock 882 heads for now (will be getting a set of the 23 degree Trick Flows this summer), Performer RPM intake, Holley 750 Vacuum secondary, Th350 with 2200 converter, stock 3.23 geared rearend for now (getting 9" later on), Headman shorty headers, custom 2.5" into 3.5" Y pipe into M.A.C. offroad pipe and M.A.C. cat back system. So far car has only been to the track twice and is having sever traction problems but is running 60'-2.34 1/8 mile-9.2 @ 79 MPH.