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Need Advice on 700r4 swap

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Old 08-09-2001, 09:21 AM
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piratemike
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Default Need Advice on 700r4 swap

I am interested in swapping a 700r4 into my '81. I would like to talk with one of you who has been through this and can offer any helpful hints. Also, did you buy a kit complete with trans or did you get your trans seperately? I may get a trans to rebuild , if so, what year model trans should I be looking for while scavaging the salvage yard and what is the easiest way to identifiy a 700r4.
Any info would be greatly appreciated.

Mike
Old 08-09-2001, 12:04 PM
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C3 Shark Tank
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Default Re: Need Advice on 700r4 swap (piratemike)

Hope this helps, any questions just email me.
http://www.sharkwerkes.com/sharktank/tech2/tranny1.html
Old 08-09-2001, 06:35 PM
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MIKER
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Default Re: Need Advice on 700r4 swap (piratemike)

C3 Shark Tank obviously has the best information going about the swap but I am attaching a cut-n-paste from one of my previous posts about the swap.

I just finished installing a ’92 700R4 into my ’80 along with a new 383.
Not counting the price of the transmission itself, here is a list of the things that I did and the parts that I purchased.
- Dipstick tube and indicator for 700R4 from Bowtie overdrives ~$22.
- Adapter kit for TV cable to stock Rochester carburetor, from Bowtie overdrives ~ $45.
- Changed from electronic speedometer sending unit to a mechanical gear driven unit from Bowtie overdrives ~$45.
- Had the drive shaft shortened and new U-joints installed at local shop ~ $100.
- The drive shaft yoke from the TH-350 worked in the 700R4
- Modified stock cross-member. (moved the mounting pad ~2” back and moved emergency brake cable over away from the U-joints.)
- Modified the original TH-350 shifter bracket that mounts to the side of the transmission pan. (The distance between the pan bolts on the TH-350 were ~3 ½” apart and the pan bolts on the 700R4 are about 3” apart).
- The stock speedometer cable is supposed to be able to reach the extra couple of inches required. I can’t verify this, I had to purchase a new one because my old one was broken. The new one came out about 12” longer than the old one.
- I will modify the shifter guide plate located in the console below the shift lever to allow placing the shifter into 1st gear. I’ll save this for another time because it is not critical.
All in all, the modifications for the swap weren’t nearly as bad as I thought that it would be. I worried most about the cross-member modifications but a talented friend using a welder, cutting torch and tape measure made short work of it.
I’m just guessing, but if you have all of the parts and access to the tools needed, I think that you could tackle it in one weekend with help from a friend.
As far as transmission selection, I’ve always heard to go with a 1988 or newer model 700R4. The prices can range from as low as ???$ for a used one up to ~$1200 for a brand new one.
Go to Smokemup.com http://www.smokemup.com/utilities/calc/mph_range2.cfm Use their gear ratio calculator with the 700R4 selected to determine what your cruise RPM will be with your current rear end gear ratio.
Go to www.bowtieoverdrives.com to see their information.

Mike


Old 08-09-2001, 08:47 PM
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Gary79
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Default Re: Need Advice on 700r4 swap (piratemike)

piratemike,miker has given you some good advice and sources. i used bowtieod for the tranny and all the other parts. i bought their conversion tranny plate,$90,that allows you to bolt up the 700r4 to the original x-member.i lifted the emergency brake cable up about 3-4 inches and then fashioned a clip around the cable and bolted it to inside of the tranny tunnel on the drivers side. it works fine,but in all honesty i'm a person who doesn't use an emergency brake very often on anything i drive. i've had bad experiences with emergency brakes not releasing when they should.anyway i understand bowtieod makes a new x-member that moves the emergency brake wheel out of the way.if you buy the shift conversion kit from bowtieod it includes the console plastic piece with the od added,it also includes the mount that goes on the side on the tranny for the TV cable.on my 79 the TV cable is mounted to a bracket that is secured by the carb mounting bolts,i reused this as it works fine and is stock. the kit also includes a new detent plate to go under the console for the extra gear or shift position.it is not neccessary to remove the stock one,just hold the new one up to the existing,trace the extra notch onto the old one,and file away. in 5 minutes you've got the notch without removing the plate.you want a 700r4 tranny,'88 and up.these trannys look like a th350,except the tail is longer and the pan doesn't have the "missing corner" like the th350 does.the pan is almost square. the pan being square will almost block were the exhaust goes thru the x-member.this required some custom bending by my local exhaust guru,but no real problem. i used a harness kit from TCI(thru Jegs) to achieve my 4th gear lock-up and a bosch relay from bowtieod,connected to the brakelight circuit to turn off lock-up.i obtained everything from bowtieod,except the harness,costs about $1500,including shipping.i could have got by cheaper,but i saved time by ordering from bowtieod,less running around.and steve holmes will give you a lot of good advice.they also include a heavy duty torque converter and he said they "beefed" up my tranny to handle the 300+HP ENGINE. I did this conversion in my garage myself and had never done anything like this before.talk to steve at bowtieod and he can tell you what you'll need.use your common sense & don't get in a hurry. a local shop shortened the driveshaft and installed new u-joints for $86. the amount to shorten is best checked by measuring the old tranny and the new tranny,the difference is the amount you want to shorten the driveshaft.

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