Thread: 350 turbo or 700R4

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what transmission is the best to use for hotrodin i have been told the 700R is good but has a lot of problems with it but i want overdrive so i can cruise on the highway without having a lot of high RPM s or would i be better runing the 350 turbo and not have any problems i have two transmissions i have a 700 R and i have a 350 lockup so guys let me know what would be the best transmission to use other than the 4L80E or the 4L60E cause i don't wanna haft to wire the 4L80 E or wire the 4L60E and yes guys i want a auto transmission



thanks for everyone info!!!!!!!!

Originally Posted by Southernboss84

what transmission is the best to use for hotrodin i have been told the 700R is good but has a lot of problems with it but i want overdrive so i can cruise on the highway without having a lot of high RPM s or would i be better runing the 350 turbo and not have any problems i have two transmissions i have a 700 R and i have a 350 lockup so guys let me know what would be the best transmission

Th eonly real issue with the 700 is the setting of the trans pressure. Old timers were familiar with a kick down cable and assumed this was the same but it isn't. Setting the cable and the geometry for throttle connection is crucial.

It's not hard now as a few companies have the setup dialed in so it's basically a bolt in and verify the pressure then your good to go! If I already owned the box, it's what I would run!

Do a google search for 700R4 settings, it's amazing what you'll find for help.

I asked that same question (Of a local race transmission guy) before I built my Nova. I asked what is best for me. I plan of mostly street but a once in awhile trip through the 1320. I said I have a TH 400, a TH 350, and a 700R4. I was told to use the 400 as the expence of building a 700R4 to take the punishment would far out weigh the cost of the added gas it takes to use the 400. So the TH400 is what I'm using. You never mentioned what engine your using. You can always use a higher rear gear too.

i am using a chevy 355 cffisher if i was to use a 350 turbo or a 400 turbo and going about 70 mph instead of doing 3000 or 3500 rpms how would i get it down to 2000 rpms what gears would you use and still have a good take off and a decent pull from the line thanks 34_40 for the info iam going to do some more research but iam not sure what iam going to run yet 34_40 if i do run the 700R what do you do about the plug on the side of the 700R?

Originally Posted by Southernboss84

i am using a chevy 355 cffisher if i was to use a 350 turbo or a 400 turbo and going about 70 mph instead of doing 3000 or 3500 rpms how would i get it down to 2000 rpms what gears would you use and still have a good take off and a decent pull from the line thanks 34_40 for the info iam going to do some more research but iam not sure what iam going to run yet 34_40 if i do run the 700R what do you do about the plug on the side of the 700R?

Sounds like the 700r4 is the way to go. Higher gears will turn you car into a dog off the line.

As long as you're running up to about 400 HP, a build with some upgraded clutches, a "Beast" sunshell, Vette servo, a nice wide 2-4 band and a shift kit if you like is all you need.

What year is your 700r4? I only use 88-92 units.

For the wires, pick up a TCC lock up kit. You can get a brake switch from a car that came with cruise control to wire it thru.
2004R / 700R4 Lockup Wiring Kit - TCI® Auto

As mentioned above, its crucial to have the cable set dead on so do some research on that. You can fry one in 100 miles if not set correctly.

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Based on the info you provided in your original post, I'd still go with the 700r4. If your not fixed on the o.d., the 350 is a good choice too. (since you already own them.)

There must be millions of them on the road and they work fine, it's all in the setup. If you do the research and make yourself familiar with the settings and what's required, I'm certain you'll make it all work and be happy with your selection.

Pugsy provides some sound information, check out the link. It's really pretty easy.

Originally Posted by 34_40

Th eonly real issue with the 700 is the setting of the trans pressure. Old timers were familiar with a kick down cable and assumed this was the same but it isn't. Setting the cable and the geometry for throttle connection is crucial.

It's not hard now as a few companies have the setup dialed in so it's basically a bolt in and verify the pressure then your good to go! If I already owned the box, it's what I would run!

Do a google search for 700R4 settings, it's amazing what you'll find for help.

You're absolutely right; the variable pressure valve body is the weak link in these 700 R4s. If the cable isnt adjusted correctly, you'll smoke the trans in a short time. TCI makes a constant pressure valve body that eliminates this problem. I put one in my 48 but do not have it on the road to test it yet.

TCI has all you need to cover a 700R4 rebuild.Beast sun gears to huge 11% lager surface servos and the constant pressure valve bodies where the TV cable is used then as a kick-down cable for passing gear.Where the 700R4 might have a down side is there is a big difference between the gear ratio of first to second.Nothing you can do about that,but the O/D more than compensates for that.For me,TCI's customer service and tech support has been first class.Window shopping:

High Performance Automatic Transmissions & Parts - TCI® Auto

Originally Posted by falconvan

You're absolutely right; the variable pressure valve body is the weak link in these 700 R4s. If the cable isnt adjusted correctly, you'll smoke the trans in a short time. TCI makes a constant pressure valve body that eliminates this problem. I put one in my 48 but do not have it on the road to test it yet.

The constant pressure valve body is an waste of money. The cable has one "setting" only and no "adjusments" in between.

Sure fire method: First thing is to determine if your throttle pedal pulls carb or throttle body bellcrank to WOT. Have someone step on the gas pedal to the floor and then try to pull manually by hand to see if the throttle will open up more. If this checks out, set the TV cable so that the bellcrank on the carb or throttle body pulls it exactly to max pull without stopping WOT from occurring. To check this, I like to pull the TV cable clip off the bellcrank, move the throttle to WOT, pull the TV cable frwd beside the clip where it hooks on and you will see immediately if its close.
Next is to make sure the plunger on the valve body is fully depressed when the gas pedal is floored. A visual of this with the pan off will help. The reason for this is that if you have a bad TV cable and its hanging up in the sheath, it will feel as though you have it set right but may not be actually burying the plunger in the valve body. (Ask me how I know this little nugget even though I had ordered a brand new aftermarket TV cable)

Setting the cable properly first is the key to a happy 700r4. The fear of this "setting" is making TCI some dough I guess.

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I knew of a guy many years ago that made a overdrive adapter for the turbo 350. I know that he is not making them anymore, but is there anyone else that makes them?

Baiscly he removed the tail section and replaced it with his own that had an overdrive unit in it.


Edit:
Guess I should have looked it up first, Gear Vendors sells one.
http://www.gearvendors.com/

TCI sells a 6 speed Bug.But it's $$$$$$$$$!!!!.