El Camino Central Forum banner
1 - 12 of 12 Posts

· Registered
Joined
·
237 Posts
Discussion Starter · #1 ·
Just got a '68 with a rebuilt 400 (+30 over) engine and 400 trans.

With gas being what it is, would like to improve mileage on trips between towns.

Want to keep the 400 trans, so looking into adding a Gear Vendors type overdrive.

Anyone done this?
Alternative choice?

No interest in having a more modern (weak) transmission and complicated torque converter set-up.
 

· Registered
1966 El Camino
Joined
·
2,302 Posts
Helped a friend install one in a 69 nova backing up his 496. required some floor modifications to make it fit. The OD ratio really isnt enough IMO but he likes it. No lockup of course so there is still slip in the assembly, unlike modern transmissions.

As far as the so-called weaker transmissions go, you can build any of them to be as strong as a TH400 for the amount you will spend on a GV overdrive, and I'm pretty sure they will be lighter than the TH400/GV assembly.

All that said, the GV units are rock solid and can take a beating, they are another way of skinning that cat, if its the path you want to take, go for it.
 

· Registered
Joined
·
2,102 Posts
i would be a little leary of the 200r4 behind a 400. but that is just me personally. i have a friend with one behind a 472 olds in a g body and is happy with it. i prefer the 700 and dont want a debate over it just just my personal choice. you loose a lot of fuel milage with the gv unit because of converter slippage. secondly you shorten the life of trans and converter because of the constant slipage and subsaquent exess heat . not to mention the extra 35 hp the 400 burns just going down the road. a rock solid trans but not the most power/fuel effiecient choice
 

· Registered
Joined
·
237 Posts
Discussion Starter · #7 ·
Found GV at $1K, need to scrape up funds.

Found GV unit with the correct adapter at $1K, need to scrape up funds to buy it quick.

My understanding is that the 400 trans is pretty bullet-proof, but not as efficient as a 350.
Never heard that it eats an extra 35 HP before!

I also recall the newer factory OD trans have some tall jumps from one gear to another, and are a bit weak unless rebuilt and strengthened.

Also know more than one person who had problems related the "TV Cable" adjustment, and burned them up. :banghead:

The GV unit also keeps with the "Old School" somewhat vintage theme.
A trans cooler will be fairly simple to upgrade.

NOT going to visibly "Modernize" this ride, max wheel diameter 15", door handles stay on, bumpers remain chrome, etc.

Really only need the GV for longer trips, unlikely to be engaged around town.

Looks like I need to get some pics of my '78 "Stealth SS" (Diablo?) and the extra parts then post it for sale!
 

· Registered
Joined
·
2,102 Posts
i ran a 700 for years behind a 500+ hp 406 with good parts and was great the parts to make it live with a stock 400 is minimal.they have a pretty steep drop off in the 1/2 shift but the others are fine and with the torque of the 400 you wont notice it much. the gv unit you will need a custom crossmember and drive shaft. with both od trans you can use your current crossmember.the 700 can use your shaft with a yoke change and the 20r4 needs a longer shaft.the gv unit and the 400 will both eat up hp that one of the od trans will use to get your car there. it is your car and do as you wish but i think you have much better options available to you. the tv is very simple to adjust and once done it is set until you move it in some way
 

· Supporting Member
Joined
·
750 Posts
My 383 stroker 450hp, 350 beefed up tranny, and now a GearVendor unit....I Love it!
The GV unit with adapter weighs about 45 lbs. I raisied the car up about a foot and a half.
Installed the unit with one hand!!!!!!!!!!!!!!!!!!!!!! Had a new drive shaft made and I modified the cross member myself. I cut an "I" in the floor, really didn't have to, I just wanted to see for sure the clearance.
At 70 mph I've dropped 700 rpm :nanawrench:
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top