E=MC^2 Posted January 20, 2012 Share Posted January 20, 2012 I have a 72 MC with a 350 that was rebulit bored .30 over and has a mild cam. I do not know what the heads are. It has a th350 with a shift kit and a floor shifter. I want to put a better transmission in. Maybe a 700r4? I dont plan on making 500+ HP or anything. I will be doing the occasional burnout street drag racing and taking it to the drive in. What I got out of all the information ive read about the transmissions that I can swap in is that the th350 is solid and can handle some power but it is just a 3spd and screams down the freeway. The th400 requires more power to turn its internals and I will not be going for big HP so its between the th350/700r4. I know with the 700r4 Ill need to run a tv cable and I will need to shorten the driveshaft and move the crossmember back and drill new holes. None of that should to be an issue. Now I know enough about trannys, I can swap them but I will not be rebuilding one myself. If there are any transmission Guru's out there let me know what you think I should do. Rebuild the Th350 or swap a 700r4. I would really love a 4spd manual but that conversion is a bit too expensive. Quote Link to comment Share on other sites More sharing options...
monte70car Posted January 20, 2012 Share Posted January 20, 2012 another 4 speed trans to look at is the 200r4 which has a closer gear set in it. The 700r4 has a big drop from first gear to second first in the 700r4 is 3.06. I've made the swap from a 350th to a 400th then to my current 700r4. When I changed to the 700r4 we put a 350th front yoke on the drive shaft as it's stronger then the 700r4 yoke. The 700r4 I have can handle 450hp and it has the goodies in it. Check around for the best price on the trans you want. My came from bowtie overdrive out in Cal. It ran about $1700 with a 2400 stall and it came as a bolt in and go - the drive shaft needing to be changed. Quote Link to comment Share on other sites More sharing options...
E=MC^2 Posted January 20, 2012 Author Share Posted January 20, 2012 I was looking on my local Craigslist, I could get a 700r4 out of a 92 camaro with the TV cable for 250. I dont know enough about these trannys, you think the 2004r is better for my application? Will it be easier to swap? Quote Link to comment Share on other sites More sharing options...
monte70car Posted January 20, 2012 Share Posted January 20, 2012 it will be a easier swap as the drive shaft wont need to be shorten both trans uses a tv cable and if its not set right you can burn up the trans. search the net and you'll see the pros and con's of both trans and the swap. Quote Link to comment Share on other sites More sharing options...
Leghome Posted January 20, 2012 Share Posted January 20, 2012 I have a 700R4 in my 72. I am really pleased with it but I need to have a local tranny guru do a little fine tuning for me. It does hit second gear pretty hard when you get on it. It will bark the tires when it shifts. Gas mileage on the highway with the 3:73 pos is around 20MPG running 70mph. Quote Link to comment Share on other sites More sharing options...
E=MC^2 Posted January 20, 2012 Author Share Posted January 20, 2012 So the 200r4 uses the same drive shaft length and I can use the same yokes? The next step is choosing a torque converter... I understand how they work but which should I get? Does it matter if its a stall or not? What stall range should I get?? Quote Link to comment Share on other sites More sharing options...
680HPStroker Posted February 2, 2012 Share Posted February 2, 2012 In the end either the 200, or 700 will get the job done, but stock for either will be nothing more than a grenade waiting to blow. Stock both transmissions are weak and can't take any power over what they were originally built for which wasn't much. If you don't have a local shop who has extensive experience with building performance versions of either transmissions go with a reputable builder like Bowtie Overdrives, Gearstar, or P.A.T.C. Your tranny builder is your best source for choosing the best torque converter for your application. As far as a 700R4 goes you can close up a good amount of the 1-2 gear split with tranny tuning. I know this as I owned one. Quote Link to comment Share on other sites More sharing options...
BURNOUT BOX Posted February 3, 2012 Share Posted February 3, 2012 the 200 4r would be alot better to use IMO.I did a 200 4r rebuild in my 85 monte ss and used a 3,600 stall converter with a Constant Pressure Valve Body http://www.performancetransparts.com/2004rconstantpressurevalvebodystreetstrip.aspx With this the cable will be for shift points,The 200-4R is very close to the legnth of a TH-350,No need to cut the drive shaft, Quote Link to comment Share on other sites More sharing options...
Dans '70 Z20 Posted February 5, 2012 Share Posted February 5, 2012 As stated neither in their stock configuration would last long even behind a mild 350. If the questions was asked a few years back the 700R4 would be the only answer. Reason being is due to the low first gear they started making performance upgrades available for these far earlier than the 2004R. But over the past few years there has been many performance upgrades made available for the 2004R to help make them stronger also. Due to the low first gear of a 700R4 the 1 - 2 shift causes 2nd gear to hit hard. Not too much of a deal on a small block, but where the problem lies is putting it behind a big block. Due to the torque ranges of a performance big block often they would blow out 2nd gear hitting it hard each time. The 2004R provides a similar gear split as a Turbo 350/400 just with the addition of an OD. In your case it doesn't sound like your building a drag car. If you already have 3:31 - 4:11 gears in the rear OR are happy with the cars performance now and just looking for an OD I would stick with the 2004R. If you have dead gears in the back and not looking to touch the rear ....getting a 700R4 may wake the car up a bit while giving you overdrive. Keep in mind the 1-2 shift will not be as smooth as your used to. You will have to move crossmember and shorten driveshaft. My two cents. Quote Link to comment Share on other sites More sharing options...
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