Hi there, running a 85 IROC with a LG-4, softly modified. Thinking of swapping the engine to a ZZ-4, will my 700R4 handle it ?
Does anybody know the weight difference between those engines ?

Thanks

85 IROC-Z, double air snork., Eibach Pro-Kit, Tinted window, SS-Hood, sbfc. ...

 

I was told by a few people that a healthy 700R4 can "survive" 350hp for a while, though your going to eventually kill the tranny.

The ZZ4 is the 355HP motor I think, it has like 400lbs of torque though.....I'm a pessimist...so I would think if you plan on going hard on the weekends you'll want to be ready to put in a better 700 or some other tranny.

As for anything else, I'm doing a 350 swap right now. It's not that bad, just time and patience. Be ready to spend extra $$....things just pop up, nothing serious, but it's gonna be a few 100$ here, 50$ here, basically I'll probably have spend 2200-2700$ by the time I'm done, and I was "hoping" to spend like 1500-1800$. Mainly you don't realize what you need until you are at that point no matter how much you prepare...and you end up with down time getting parts. My local pep boys doesnt' sell high torque starters....so I'm waiting for a starter....

 

If you beat on it at all a stock R4 will need a rebuild even on a stock L98 after a while. So with a ZZ4 depending on how you drive will last for a while.....but not forever. Just be prepared for the inevitable

 

Your car is an 85, I think thats one of those older crappier 700s...I think mine (87) was the first year of improvements....just have money ready to get a new one...I'm already planning on doing it during spring break...I hope mine lasts that long.

 

the 700r4's were different in 85? oh really.. excellent. mine is toast, no od in 1 2 or 3. grinds in park.

85 2.8 berlinetta

 

yea, i think 88 and up is the best year, in 87 they upgraded some crap in it, or so im told...i just read the thirdgen.org year by year history and it said the 700r4 got a 10vane pump and some other crap to help make it better....who knows...all i know is my tranny has 87k on it, and it shifts perfectly, and works great....i hope ill still be saying that in december

 

Check around online for tranny builders. I know there is one called monster trannies or something that sells on ebay. I believe it's like $700 for an r4 ready to go (minus TC) I think taht might be the best way to get a nice warranty on it. I paid $700 to have mine rebuilt and I don't have a warranty. I have put about 8k miles on mine since the rebuild and have recently started spraying nitrous and I haven't noticed anything wrong yet.

Brett

 

people at www.rosslertrans.com have been building trannys for Lingenfelter. I have one of their rebuilds that lasted for 3.5 years with me beating on it with one of the LPE 383 engines.

 

Yes in '87 they upgraded to a 30 spline input shaft. Being one of the better improvements. You can update the older 700's to that input shaft, but you have to replace the front drum (it's attached to the input shaft) and the pump housing (upgrade to a 13 vane pump at the same time).

By no means were the first updates done to TH700R4's in '87 though. Transmissions are changing constanly, they probably had an upgrade for them two weeks after they first debuted. Have you ever looked at a rebuild manual for a transmission??? You have to update all kinds of stuff.

As an answer to your question, if the tranny is holding up fine right now, go ahead and use it. I had one in an '83 Z28 (first and worst year) that I drove till a 170,000 miles of constant abuse. Well I blew up the engine before the tranny. Last winter I blew up my T5 in my '90 IROC-Z at 100,000 miles and I threw that 700 in till I could find a decent T5 replacement. Well I beat the hell out of that car and the tranny is about gone, but I took out the rearend before the tranny. So they can take some abuse.

Martin

 

Hi folks

Thanks for all your infos, well my car has about 80k miles and the tranny works fine so far, well I probaly will change the tranny too or instead of a ZZ-4, I will go for a LT-1.

Danny