Hello Everyone,

I posted a question last week about the 700R4 versus the TH400 and what would be the best choice to put between my 396 punched to 402BB and 3:55 12 bolt posi.

I got a lot of great replys from you guys and most said go with the 700R4. With that I did a survey of some local and internet found tranny shops that specialize in drag racing and muscle cars and they all said I was crazy to go with the 700R4. They agreed the overdrive is great and first gear is extra low, but the general consensus was that they do more rebuilds on 700R4 than they can keep up with.

Most of them recommend the TH400 and said that I will never have a problem. Also that if I want the overdrive . . . . save up and install a Gear Vendors Under/Ovrdrive.

This is a big ticket item at $2,000 but would give me similar performance to the 700R4 but can not be destroyed. This will give me 6 full throttle close ratio shifts.
Trans Ratio 2.48,1.93,1.48, 1.15, 1.00, 0.78
and a final drive ratio with the 3:55 gears of 8.95,6.98,5.40,4.20, 3.55, 2.77.

The 700R4 is by far the more economical option at say $1,500 for a turn key "built" transmission. The TH400, Gear Vendor option - $800 + $2,000 is almost double but I would have a layout that would be very reliable and hard to destroy. A testimonial to that would be that ZR1 Corvettes did not have a 700R4 but a TH400 with a Over/Under Set up. If I am worng about the ZR1 don't bite my head off but it is accurate to one of the high end Corvette's.

Back to the point. . . 12 - 18 months down the line and one too many hole shots and the 700R4 might be gone and then call for another $1,500. If that happens the better investment is the $2,800 for the TH400 Gear Vendor.

Finally to the questions:

Is the TH400/Gear Vendor Set-up overkill for a street/strip 1967 Camaro Convertible with a 450HP BB and a 3:55 12 bolt posi?

Do any of you have experience with running a splitter - Gear Vendor Under/Overdrive?

Want more info before you answer - check out www.gearvendors.com (http://www.gearvendors.com) to see why I am interested

Also, if any of you have to ability to throw a hook on a low interest loan to finance my potential Under/overdrive . . . .give me a yell.

Thanks guys
jknotts@dca.net

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67' SS Nantucket
Blue Convertible
jknotts@dca.net
Pennsylvania

I agree about the 700R4 and 4L60E. I've been running my Impala SS with a 175 N2O shot, generating around 550hp. So far, I've got 2800 bucks invested in my 4L60E over 3 years, and right now it's down again.

I've finally decided not to throw good money after bad, and am going to the TH400, and later, when finances permit, will add the Gear Vendors. I'll have to live a while with 65mph cruising speeds at 3500rpm, but this is better than always throwing money at the trans.



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SSMOKEM

1995 Impala SS "Cherry Bomb"
Best ETs: faster than my '65 pickup
Mods: 93% stock

My Super Impala SS Website (http://home.cfl.rr.com/cherrybomb/)

jknotts, I ran into the same thought process when I was building my car.
I bought the ZZ-502/502 GM motor, and also the Currie rear 9" 370 rear. What do I put in between the two.
I talked to alot of people, racers, cruisers, and even put up a post awhile ago. I wanted the overdrive of the 700R4 for the highway but I'm wasn't about to baby this car. I put way to much money into this car to pamper it, I'm wanted to enjoy the h*^* out of it. Tire Co's love me.
As I read your post you punched out a 396 to a 402. It's obvious that you aren't going to baby this car. After doing about 1 year worth of burnouts and with all that torque you will blow up the 700R4. (Burnt money)
Go with the T-400, after a year you can order the Gearvenders overdrive unit with the money that you would have spent on another trany, then you will have the complete setup.
I bought the HD Hughes T-400 from GM (Pace)with a 2800 stall. I went to the wharehouse to pick up the items and it ran about 1,100.00.
Next year I'll order the G.V. unit and it'll be money well spent. The only draw back is the drive shaft. I bought a Denney's Al. shaft which ran 475.00. It looks like I'll be ordering another shaft next year also.
So if you are going to go this route don't purchase a custom drive shaft, use a stock one till you order the G.V. unit.
Look at that, I might have just saved you a few extra bucks.
Enjoy, and let me know how you make out.

502 Bob

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69 Coupe LeMans-Blue
Frame-Off Resto, ZZ-502/502 Crate, A/C, Griffin Rad., March Serpintine Sys., 2800 Stall with Hughes T-400, Currie 9" with 370 Gears.
www.mobiletools1.com (http://www.mobiletools1.com)

The high price of a quality 700r4 converter compared to a th-400 converter will narrow the price difference as well.

I have been looking at the GV unit too and it looks great. I wrote to them and they answered all of my questions and even sent me an informational catalog about the product. I like the fact that it makes the tranny more of a close ratio while all of the overdrives have pretty big drops in rpm between first and second. When money permits, I am definately going with a GV unit. I have also heard that some 'Vettes came with the TH400 and a gear splitter. Running a car through desktop drag with the 700 as opposed to a TH400 with GV under/overdrive results in about a half second quicker 1/4 mile times because the engine stays right in its power peak.

Make sure you know what your getting into before you purchase the GV unit. Other posts on this board indicate that you must push a button to engage the GV split gears. I read that the GV unit takes its sweet time shifting into gear. Again, do the research, because I don't remember the details. Another good source for info on the GV unit is the Chevelle site.
Rick

yeah, the thing requires a 12V push button control if you want to shift manually. They also have an auto feature that just kicks in overdrive after third gear. I have heard that they shift pretty hard and fast myself.

Hey J,

I've got one and it's great (in my 68 Chevelle with a 4.10 gear). It is very well designed and complete, however, you may have to "massage" your floor to get it in.

I ran into the same dilema as you with the 700R4 vs Gear Vendors unit and I opted for the Gear Vendors and a TH400 because I didn't want anything breaking.

The Gear Vendors unit can certainly take a pounding and I believe just about any power that can be thrown at it. However, even though these units are designed to be used as gear splitters and overdrive, they take almost 1 full second to engage. Disengagement is almost instantaneous. To effectively use the Gear Vendors as a gear splitter at the track you would need a computer and an air shifter. To try and time it all, engage O/D in 1st, then disengage as you shift into second, etc would be really tough. I suppose there is somebody out there from the video game generation that could effectively do it though.

If you want any additional info drop me an email.