Yea no way I can afford a gv overdrive

 

I've had both in my truck. I liked the TH400 but I ran 4.10 gears and it was a bitch to get on the freeway. I have a 25 min 65mph freeway drive to work and it got old. I really like my 4l80e. I just like having the ability to tune shift points, firmness, ect.

 

I agree. If n/a I would be hesitant to swap though. A big converter and gears would make the drive ability a lot worse, and without those on a n/a setup you are leaving some on the table.

A turbo setup would be different tho. Most people here run small cams,small converters, and streetable gears with a turbo setup. This IMO, makes a th400 swap a lot more driveable.

 

One point I haven't seen mentioned here yet is final drive ratio. With the power level goals you have you don't need low rear end gears for a strong launch because traction problems would make first gear useless. Consider swapping to 2.76:1 gears as part of the expense of choosing the TH400 over the 4L80-E. This will keep the RPM down on the highway and move the range of shiftpoints higher up in MPH. (First gear WOT in that scenario would take you to 75+ mph.)

You're used to the wide gear ratios and overall range of a 4L60-E. With a 4L80-E you lose overall range in favor of closer ratios. A TH400 has the same ratios and range of the the first three gears of a 4L80-E but you lose the 0.75:1 overdrive making it the narrowest overall range choice of the three transmissions.

 

I just sold my th400 off because i didnt like going back to overdrive 80e swap with a circle d converter.

 

if you had overdrive before your not going to like the th400 swap.

 

It can be built cheaper, but it won't really be stronger. The OD is the 4L80E's biggest weakness at high power levels.

Not necessarily. A 4L80E is a much better option than a TH400 with a GV overdrive unit. The GV sounds nice on paper, but it most certainly has it's downsides that do not come with a 4L80E. If you do not have an electronic speedo, although it is stupidly costly for what it is, a mechanical speedo/tailhousing setup on a 4L80E is still the way to go.

 

How many gv overdrive units have you run?

 

Well I build racing TH400s and 4L80Es professionally, so I've seen a number of them over time, but have not run one myself. My old boss, who owned the shop I worked for (Jake's Performance), had one on his Chevelle and also hated it. How many TH400s have you built and how many GV's have you installed?

 

I'm not a transmission builder. Never said I was. So I've never built a TH400. I ran one in my truck for a while but I had a pro build it. I'm curious at what problems you have run into with the GV's