I want to keep my stock 700R4 and stock rear end. My motor is now starting to push 400hp/385TQ. Does anyone have any idea or stories of how much HP/TQ these can withstand and still be a daily driver?

Thanks for any help.

 

700's have been destroyed by stock motors nearly as quickly as built ones. If you take care of it and dont abuse it keep the fluid cool and clean you can use it as a daily driver for as long as the soft parts hold out. They are wear items and eventually need to be replaced. 100k is a good long life for a stock 700r.

Yours being newer than an 87 (the first couple years thru 86 were weaker) is a good point to start at. From what I have seen even on stock motors if they are abused they wont last long. If you put an extra trans cooler with maybe even a small fan on it and keep the fluid and filter fresh like maybe every 10k miles that will help in the life of the transmission.

There are several upgrades you can make like a better input shaft and just a regular shift improver kit. The "corvette" servo swap and tons of other things that you can do. This can all be done by you if you have the tools or for around 1500 you can get a built one already from TCI. They have several different power levels and one in your area should be around there. If you dont have the tools or experience to build it up yourself then it will cost you at least that much to get it done at a transmission shop.

700's arent known for their toughness from the factory but with proper care and a few upgraded parts it should be able to handle a pretty heavy foot in the power range you are looking for.

Im not plugging TCI thats just the ones Im familiar with. There are dozens of companies out there who make strong 700-r's and they all mostly do it the same way with the same parts.

Oh and the better a fluid you use the better your transmission can handle things. The hard parts arent going to be helped by it but all your softies like clutches and bands lives will be greatly enhanced by a quality fluid. Keep it cool and keep it clean.

For an on the cheap job doing a shift kit, trans cooler with or w/o fan, the corvette servo, and if you are feeling spendy the stronger input shaft. Oh and of course a higher stall torque converter will aid you.

Hope you can keep that transmission alive. Dont worry if you burn one up. They were only designed by the engineers to last 100k miles or so stock before needing a rebuild. So if it goes dont worry too much. They are frequent visitors to tranny shops and in my area a basic rebuild goes for between 400-900 without any hard parts depending on what shop you take it too. Planetary gears are bad to go out in them and that adds 50-100 depending on if you replace it with a rebuilt one or an all new one.

I got mine rebuilt with a new torque converter and a rebuilt planetary gear for 565$ with tax. I could have gotten a performance build for 900 plus tax but I dont have a big bad motor. The planetary gear wasnt damaged but it was grooved and would have failed and put metal into the transmission before it would have needed another build so better safe than sorry.

-vJ-

 

^^^^pretty good info. Personally, I'd reccomend staying away from TCI or B&M for 700r4 trans or parts. They don't seem to have a clue about building strong 700s. PATC(raptor)or Dana at Pro Built are the two companies to deal with(IMO, plus many others on this board)

- Anyhow, your stock 700 will do ok with a decent "shift kit"(transgo or superior) and a good servo(corvette or billet aftermarket). Once it hits time for rebuild, then look into some of the internal upgrades. There is much available, and a 700 can be built to hand around 700-800hp, PATC is saying they'll have one rated for 1000hp soon.
As for the rear, it could be a 10-bolt or a 9-bolt, which makes a lot of difference in strength and in available parts. Most of these cars got the 10-bolt, which can be built for decent power, but in stock form, can easily be broken. - It's a 50/50 thing. You can easily spend more upgrading a 10-bolt than what a 9" or 12-bolt will cost you, and it'll still never be as strong. A good brand gear, a decent carrier(posi) and a support cover(aluminum girdle) will probably handle the power your talking, but much more and you'll need aftermarket axles, a solid pinion spacer(cheap, so this part is almost a must anyhow) and welded axle tubes.

Much of "how much power can they handle" depends on how you drive it and how you use it. If you mostly cruise around town, playing around from time to time, they can easily/cheaply be upgraded to take it. If you start going to the track often or beating it every street night, parts can fly quickly. - The amount of traction also plays a big role in driveline life. Which is not to say that more traction is worse. Wheel hop is about the deadliest thing, good traction and aggressive launches being the next....

 

I just had a 4L60 built up this spring for my 91 Z-28 (same as Th 700 R4). I had a buddy do the overhaul, he's a local mechanic with his own pro street car. With the transmission and a custom built torque converter the bill was about 4500$ cdn. The tranny is rated to about 600 HP.

This is a list of some of the parts. Stage 2 shift kit, 7 out of 10 shift firmness, 29 sprag roller clutches, high output 10 vane pump, heavy duty drums, beast sunshell, 5 pinion planetaries, heavy duty servo kit, 0.5" throttle boost valve with plunger sleeve, hardened input shaft, 9 red eagle and 8 kolene treated steels per clutch pack. Custom manufactured 2800 stall, nitrous anti ballooning plates with lockup.

I probablly missed a few but this tranny is built to last and be punished at the drag strip.

 

Thank you for the responses. It's just what I needed to know.