Starting to ponder which trans to put into the project so I can figure mount locations. Would like to go with a 200R4 for the better gear ratios. Thought I'd pole the group to see who is able to get what trans to live (race prepped units not stock ones). Engine dyno software "says" the planned motor configuration (396 cu in small block) will be 500 ft-lbs and 550 HP, "hoping" car will come in about 2500 lbs. Probably will keep the 5:38 gears for a while, so definately want an overdrive trans.

-Greg

 

I can't believe nobody has replied to this thread yet....

Greg,

Personally, I've had nothing but bad luck with the overdrive autos. I've recently blown my fourth one. My car is down until I can put aside my house remodeling projects long enough to afford a 6 speed conversion.

For strength, a turbo 400 with a gear vendors OD unit is the best, but the cost is prohibitive. I've heard that Pro-Built automatics can build a 700 or a 200 that will last, but personally, I've had enough.

 

Greg,

I've had the opposite results as Mojo's unfortunate troubles.

I bought my 85 Corvette with 150,000 miles on it and over the next 40,000 miles I raced it most weekends with primarily 12 second time slips....I would guess somewhere around 700-800 1/4 mile passes on it over those 40,000 miles. At that time, the transmission didn't fail, but at wot it would not shift into 3rd gear, it would shift into 3rd in normal driving though. This was the 3-4 clutch pack which seems to be the first thing to fail on a 700R4... keep in mind I have no idea when I bought it if the tranny had been rebuild previously to me purchasing it or if it already had a 100,000 miles on it.

When the 3-4 clutch pack went out... I then had a 90 core 700R4 built for me to stock GM standards. Since then, I have installed a more powerful engine that consistently runs 11's.... After 10,000 miles and literally 300-500 11 second 1/4 mile passes on this transmission, I have zero problems.

The only time I had to have it take apart was after a improperly executed Transgo shift kit installation. I simply restored the valve body back to stock and have had no problems or ill effects from the several weeks it was shifting in-correctly with the shiftkit.

Another Forum member "LT401vette" has an approxmiately 600 hp stroked LT-1 that runs in the 10's at trap speeds of 125-130.... he has told me he is getting 1-2 years between rebuilds of his 700R4. Food for thought.

Not sure if its right for your application, but I think these trannies can take a little more than advertised, but of course there is a limit in their somewhere... not exactly sure where it is though.

good luck
Beach

 

If I had it to do over again 5-6 speed is the way to go. Your light weight will make a auto or manual tranny last. Your big tires will kill them. Give http://www.artcarr.com a call if your set on auto's I've heard of 200's in powerful cars.

5.36 is really pretty good when combined with 31-32 inch tall tires. My buddy has a pro-street with them and a TH400. But he is into the rev limiter at over 150 mph in the quarter mile

 

I broke three 700-R4s and 4 torque convertors last summer. I still think they are good transmissions. I have gone to a T-5 then a Tremec TKO and love the standard. I would not want the 6 speed because the 1st and last gears are roughly the same and I don't need the extra shift or added expense and bulk and weight.
I think that going to a 3 speed without overdrive is a waste. With an overdrive you get great 1st gear launch and in 4th a great cruising gear. My 4.11 out on the open road become 2.7s. 2200rpm at 60 2500 at 70
Norval

Norval

 

It's going to be mostly a street toy, so I'm not really considering manuals (besides, I hate working out clutch linkages and am not that fond of hydraulics, even less for cables). So far I've just been browsing, and most places list their street-strip models up to 450 ft-lb, 450 HP, which I "hope" to be a little over. Haven't yet called Carr , B&M, ATI etc to talk, but guess that's the next step.

The 5:38's will be a bit steep with my 29" tires (140 mph at 6000 RPM rev limit), but that should be fast enough for the street. If I go into the rear I'll likely drop them to 4:88 or 5:13's, but since the 5:38's are in there I plan to start with them.

Right now I'm still struggling with the oppsite end (front suspension) ... have found a workable spindle set, but it looks like there isn't much choice but to stretch the frame 2", so I'll have to break out the sawsall this weekend (boy how I wish I had a plasma cutter, but alas it's not in the current budget).

-Greg

 

The 700R4 is a very good Tranny if built correctly. Also, you should use a 88+ core.

I have seen stock 700R4 run 75K+ on a mild setup. One thing that I have heard from many Tranny rebuilders is to use the "D" position all the time unless you are on the highway doing a consistant speed. This way you are not constantly banging in and out of 3rd and 4th gear.

Also install a Tranny cooler, this will help alot. The cooler the Tranny , the better.

Vic


[Modified by Vic'89, 8:33 PM 9/13/2001]

 

I broke several 700R4's, but I think it was because the guy building them for me didn't know the overdrive tranny that well. I purchased a TCI 700R4 Non-lock-up and a 10" Art Carr convertor. The only problem I had then was it won't go into 4th under full throttle. I installed a full manual reverse pattern valve body and that solved that. This transmission is rated at 450 lbs ft. torque. This may last in your car because when they rate a transmission it is the amount of torque the transmission can handle for a sustained 24 hr. period. Good luck!
:cheers:


[Modified by 03QSZ06, 12:35 AM 9/22/2001]