overdrive trans for big block???

[aidanfancystang]

So I just picked up a 72 nova with a 496ci big block, the car right now sports a turbo400 but it sucks on the highway, I am wondering what you guys recommend for a good trans with overdrive that can handle my engine without too many issues.
the engine dyno'd at 496hp 550Lbft of torque.

[lbluecamaro69]

Keep your th400 as they are a very strong transmission and it sounds like you'll need one. Go with a gear vendors overdrive.it will give you twice the forward gears and bring the ratios all closer together.I have a th400 with a gear vendor od in my camaro and I haven't driven with it yet but I have heard great things.very easy to install too

[AMSOILGUY]

I just did this exact addition with my 502. I've got 4:10 gears and used to turn 3400 RPMS at 60ish now I turn 2800RPM at 70. Couldn't pay me to take it out.

[astroracer]

X3! You will not beat the price of a GV unit in your situation. If you go OD trans you should build a 4L80E to stand up to the torque of the BBC and you will not build one and buy all of the electronics to make it work for the price of a GV Unit. I have done all of the research on this while working on the van and this is the way I went. I have less then 2K into a very stout 400 and GV Unit. Of course I found a deal on eBay for the GV.
Mark

[aidanfancystang]

I know nothing about the gear vendors stuff, is there a specific model I should look for?

[astroracer]

http://www.gearvendors.com/hrgm3s.html

[csouth]

The best bang for your buck will be the Gear Vendors if you can find one used. If you have to go new, personally I would get a 4L80E from Jakes Performance or similar. His Stage 2 is rated to 750hp. With a controller you'd only be slightly above the cost of a GV. You could recoup some money by selling the TH400 as people are always looking for those. You'll need driveshaft mods with either choice.

[BonzoHansen]

My friends just did gv units last year. One behind a 502/400 in a 79 camaro. His th400 was setup perfect, the converter is great, shift points dead on so he did not want to start from scratch with his setup so he went gv. and that reasoning is sound imo. He loves the gv.

Another one in a 74 nova. 350/350. He loves his too. Down side is cutting floor braces. I'll try to find out how much he had to cut.

But I plan on a 4L80e for my 67 as I am starting from scratch and would prefer not to cut

[Steve Chryssos]

The GV/TH400 is certainly one option. Keep in mind it overlooks two of the best benefits of modern transmission technology:
-- Lock up clutch.
-- Comprehensive tuning of shift points, shift firmness, and lock up apply to match your exact application and driving style.

1-2 shift happening too soon? tune it. Want lock up in 2nd, 3rd, AND 4th? Tune it. Shifts too harsh or too slow? tune it. And tuning is super easy.

[chevnut55]

I used the G/V in my 800 hp bbc blown 55 chevy with a built th 400.
Its good and fun to split gears, but already had problems with it , I drove to a show 30 miles away that was out of reach w/o a overdrive did 65-70 on the way home the g/v speedo cable broke and did 50 on the way home. g/v charged my $5 for a new cable that broke for no reason.
If I kill this trans Im selling the g/v and installing the 4l80e.

[pitts64]

pass

[aidanfancystang]

okay I think I am going with the 4l80e option, I want to go to the bone yard to pull one to take for a rebuild, is there a specific year I should look for?

[aidanfancystang]

So I picked up the trans this weekend now on to a programmer. Who makes a better programmer for carb car?

[Poorhousenext]

Rob,

Can't speak on whose controller is best for carb applications. I would take a look at sponcer of this section of Forum, PCS. You might want to take a look not just at their controller but also at other upgrades you might want to consider for your 4L80E now or add later, some of which want work with other aftermarket controllers. I'm in that posistion right now with one of their upgrades I would love to have for my car.

http://www.powertraincontrolsolutions.com/

[Steve Chryssos]

Compushift makes the best TPS Carb bracketry, for sure. No remote mount silliness. No slop. The brackets are a direct fit for whatever carb you have.

[Steve Chryssos]

[Steve Chryssos]

We include the TPS Carb kit for free with purchase of a Compushift controller. So it goes with hot rods. It's the little things that add up in the end.

[aidanfancystang]

any thoughts on the TCI unit?

[Steve Chryssos]

Their TPS kit? I used to run one way back when. Better than the PCS version, but still cable operated. It's an extra variable. ....and you know how those "adjustable" cables kinda start to fray and stick over time? Your TPS signal is the A #1 most important variable in electronic trans control. A direct, hard linkage mounted TPS is a really good idea.

-- If your TPS jams open, the TCM will deliver excess pressure at low loads and bad things could happen.
-- If your TPS jams closed, the TCM will think you're sitting there at idle even when your getting after it. Mis informed, the TCM will deliver no pressure and very bad things will happen (unless your at idle).

[Sean Cooke]

4l80e all the way - Gear Vender is complicated when trying to go fast - I have a bone stock 4l80e behind my 700+hP with a Jakes Performance little black box to control shifting - it's awesome and cruises on the freeway just under 3k at 80mphs with a 3:73 rear gear