ripinLS1

iTrader: (1)

I have a 1999 6 speed T/A wanting to go to a 4L60e or 4L80e? 454LSX N/A motor full car 3745lbs with me in it. Expecting 650ish at the wheels. Would like to run a trans brake. Street/strip car but want to lean more towards strip. Also who do you recommend to build the trans?? RPM,Gear star ect. Also if I go to a 4L80e what do I do about the wiring harness to the trans. Please help!!!! Thanks!!!

01ssreda4

iTrader: (96)

4l80e, I dont think a 60e would be reliable at that power/weight. I would swap the entire harness for an a4 harness (your m6 harness is probably worth more $) and buy the nelson add on adapter. Then you'll need to segment swap the computer (easy) and that portion is done.

ripinLS1

iTrader: (1)

Thanks!!!!!!!

Jtm2085

iTrader: (1)

If it's mostly a race car, why not go th400?

01ssreda4

iTrader: (96)

No clue what the infatuation is with a mechanical trans when the car is already setup for an electronic overdrive model with lockup.

mrvedit

Agreed that with 650 rwhp (750+ at crank) the 4L80E will be best choice; skip the 4L60E.

I love the idea of a 454 LSX. My first car in '73 was a '70 Chevelle SS 454.

Jtm2085

iTrader: (1)

Weight, money and simplicity? If he's going to drive it everyday then sure go 4l80e. But for a car that sees mostly strip duty why not go th400?

ripinLS1

iTrader: (1)

Street/ Strip mainly street

bbond105

Then a 4L80e would be your best option with that hp level.

01ssreda4

iTrader: (96)

Weight is a wash, simplicity is a wash. I can agree on money maybe. But even then, its not ENOUGH money to offset the downsides. 4l80Es are proven to do well, used with just a shift kit. Nobody is advocating buying a $5k Jakes level 26. Flexibility with the 80e is the deal breaker. How technical you want to get is up to you but i will give you an example. I live in the south, and it gets hot and humid here. Keeping trans temps in check is a major concern when towing, racing, or running a loose converter. One of the best ways to do that when you run a BIG converter is to get it to lock, stop generating heat, and temps are easy to control in the summer. Driving around, unlocked, with a BIG converter is a disaster in our weather. If you are not maintaining at minimum converter coupling rpm, tons of excess heat will be kicked off. So it limits you in rear gearing and converter selection in my opinion. Not to mention precision controlling of shifts, being able to log trans activity, being able to tailor its entire driving characteristics to your liking. The list is endless. But yeah, go save a few bucks I dont care.

Jtm2085

iTrader: (1)

You have some good points. Regarding price, I got my th400 that's rated to 900hp with a transbrake for $1800. What would a similar 4l80e cost? I'm pretty sure it's quite a bit more. I don't have the ability to tune my own car, so that would be another expense to utilize the lock up feature of the 80e. But I'm not going to lie and say that I haven't wished that I had over drive at times

01ssreda4

iTrader: (96)

Depends on who you go with. An internet vendor? Probably 3k if I could guess. Our local guy does builds of that quality for 12/1300ish, transbrake is another 500. So price is a wash if you can find a good local builder. If you are carbed, it makes a little more sense, but for FI it doesnt cause you are tuning or paying for a tune anyway.

ripinLS1

iTrader: (1)

Pros and cons.

AnotherWs6

iTrader: (17)

But you said this in your first post.....Street/strip car but want to lean more towards strip..... What gives? Can't be both at the same time.

NA motor is gonna want some gear. This isn't a turbo car where running 3.08's is just fine. A TH400 is makes no sense for a street car with steep gears.

I'll tell you what the best trans for you is. A built T56. Save the manuals!!