Two questions.

1. How long will an '88 700r4, with a stock rebuild prior to pulling the L03 out, withstand a 402 LSx with 400-440ft lbs of torque? I do plan on babying it while the 700r4 is in it. I basically need it to get back and forth to dialysis, of all things, so Ill fight the urge to detonate the trans until I can replace it with a 4l60e. I will just need the car prior to having enough cash to replace it.

2. Who makes the best 4l60e for this setup? Leaning towards performabuilt right now simply because of the "perks" shipping, core, warranty, but I honestly know nothing about their reliability and would not want to have to ship my transmission across the country every 6 months.

 

Not very long. Hard to tell is the trans fresh or old? If you just drive easy it could last a while. No burn outs , hard launches, or full throttle up shifts they can last.

Circle D or Rossler are the best in the busniess.IMOP. If you could swing it a 4l80e is a much better trans. The 60e can work well on the street it just takes a lot of $$$ to make one last on the track.

 

Its been sitting for quite awhile, which is also part of the worry. As far as 60 vs 80, isn't there a greater HP or even mpg loss on the 80?

 

Yes but depends on what you want to do with the car. If street only car then the 60e should be ok. Heavy track use then the 80e is the way to go. if I had it all to do again I would do the 80 hands down. When I looked at doing it there were no conversion harness etc. My 60e is a 4k$ trans minus the convertor. Thats not taking into the costs of r&r the trans several times.

When I mean fresh, how many miles are on the trans.

Then if you get the trans working the 10 bolt rear will be a problem. Again not so much for a street car.

 

From my years here I have seen Performbuilt, RPM, and FLT have excellent track records of good products and good customer service.

 

The 88 700R4 is better than the early 700s but it will eventually fail. If it is in good working order I would sell it to another 3rd gen guy and use that money to pick up a good working late model 4L60e with a removable bellhousing. This will make your life easier in the long run. Your engine ECM will be able to control the transmission and when the stock 4L60e finally fails you will have a core to send back to one of the vendors if you decide to have a performance build done in the future. This will save you some money.