best for a 400 sbc?

[ssick chevelle]

hey all, im currently in the market for an updated trans. i was looking at the 700r4 becausei drive the car daily on the freeway and city? any other opinions? ive also heard good things about the 4l80?

[jknight16]

I had a 700R4 behind my 400 SBC and it actually lasted for quite a while. 15-20k miles.

If I had it to do over again, I would skip the hassles of the TV cable and go with an electronic trans, like a 4l60e or 4l80e. I'm 100% sure it would drive better, hold the power better, and last longer. The downside is obviously cost.

[ssick chevelle]

wow thanks alot, a noticble differance and a longer wear life would be worth my money. im asssuming alot more modifications would be needed for the 4L?

[jknight16]

Well, yes and no. It's more about the parts required. With any 4LXXE GM trans you are going to need a transmission computer to handle the shifting for you (taking the place of the TV cable) and a Throttle Position Sensor (TPS). This is no big deal in terms of complexity or installation, but does add to the cost. The performance/drivability benefits are pretty substantial too though. Twist Machine is a great resource for these swaps. Steve knows this stuff inside and out and can get you hooked up everything you need, even if you don't want his paddle shifters.

What vehicle are you putting this in? The answer may influence whether you consider going with a 4l80E or not as they are physically larger and a little more difficult to fit in an unmodified trans tunnel. If you don't mind modifying the tunnel a bit, then it's a non-issue.

Do a search for 4L80E, read til you're cross-eyed, then call Twist. This is one swap where research and preparation will be one of your most valuable tools.