Guest Anonymous Posted September 12, 2002 Share Posted September 12, 2002 Hello, I’m busy with other stuff right now with my ’77 hybrid Z conversion, but one of my future projects is to replace the turbo 350 transmission (3 speed automatic) with a 700R4 overdrive transmission. Driving at highway speeds (70MPH) with the TH350 doesn't cut it. I'm turning almost 4000 rpm at that speed. For those in the know, or who have done this swap before, what is involved? 1. Will the 700R4 bolt up to the 350 engine without modification? 2. Is there a difference in length between the TH350 and the 700r4? In other words, will I have to change/modify the driveshaft? 3. What else is involved? 4. I’m using a B&M Megashifter now. Will I have to replace it, or can it accommodate the 700R4 transmission? 5. What about the speedometer? 6. Any considerations for transmission lines, or other connections? Any responses will be greatly appreciated! Thanks, guys. Rick Quote Link to comment Share on other sites More sharing options...
Mike C Posted September 12, 2002 Share Posted September 12, 2002 Yes it will bolt up to the 350. Yes it is longer and will require a shorter driveshaft but uses the same output shaft spline so your yoke is OK. The rear mount is further back and will require relocating the trans crossmember. Some 700's have mechanical speedometers that should hook right up to what you have now. Others are electriconic speedos. The newer megashifters work with either 3 or 4 speed autos, not sure about yours. You cannot use your TH350 torque converter and must get one for a th700r4. You will have to get a torque converter lock up switch. Easiest way to do that is to get one that locks up the converter only in OD. You will also need a connection to the brake pedal that unlocks the converter when you hit the brake. I believe the cooler lines need to be slightly longer, but don't recall for sure. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 12, 2002 Share Posted September 12, 2002 Thanks for your reply, Mike. Another question that I forgot to add to the first post... Will the 700R4 require that the transmission tunnel be modifided so that the tranny has enough clearance? Rick Quote Link to comment Share on other sites More sharing options...
fl327 Posted September 12, 2002 Share Posted September 12, 2002 700r4 is a little wider, andyou want room for the oil lines too, trans is about 3 inches or so longer than 350. trans mount mods are needed, but minor, uses same bushing after all. you will need a converter for 700r4, should bolt right up to the flexplate. a little fluid, a driveshaft, and some heaving and youre good to g. Quote Link to comment Share on other sites More sharing options...
Guest aryanramsey Posted December 28, 2005 Share Posted December 28, 2005 quick question about that, i am doing the same swap,but purchased it off of ebay now it has a torque convertor already on it,so besides shortening the driveshaft the different mounts what else would be needed? Quote Link to comment Share on other sites More sharing options...
nullbound Posted December 28, 2005 Share Posted December 28, 2005 checkout this site for answers to all your questions about the swap: http://www.700r4.com/faq/faq.shtml i swapped from a th350 to a 200-4r and everything i needed was there. check out their wiring made ez and tv made ez kits. Quote Link to comment Share on other sites More sharing options...
icewtr Posted January 3, 2006 Share Posted January 3, 2006 the 700r4 is the same length as the th350 with the long tail housing on it. Quote Link to comment Share on other sites More sharing options...
icewtr Posted January 3, 2006 Share Posted January 3, 2006 you might also want to check the year of the 700r4 On the passenger side of the transmission, right above the pan gasket, towards the rear, there is a small flat spot with numbers stamped into the case. The first number is the year. If it says 9 it's a 1989. The 1982-1984 are 27 spline. The 1985-up are the 30 spline. Quote Link to comment Share on other sites More sharing options...
Lewis Maudlin Posted January 3, 2006 Share Posted January 3, 2006 Everything Mike said was correct. I have done the 700R4 too. One thing to watch out for is the 700R4 is a weak tranny unless you have one that is built. I went through one tranny with 2 rebuild before opting to spend $1400 on a built 700R4 to handle the big motor and light car. The overdrive is a must if you intend on driving your car more than a few miles. Quote Link to comment Share on other sites More sharing options...
BirdmanZ Posted January 3, 2006 Share Posted January 3, 2006 the biggest thing to remember is the tv cable adjustment. improper adjustment and the tranny wont last to long. Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted January 3, 2006 Share Posted January 3, 2006 I hear the 87 and later 700r4 are a litte more tougher. I had a th350 out of a truck, it was the same length as the 700r4 so I lucked out and didn't need a new drive shaft. Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted January 3, 2006 Share Posted January 3, 2006 I hear the 87 and later 700r4 are a litte more tougher. I had a th350 out of a truck, it was the same length as the 700r4 so I lucked out and didn't need a new drive shaft. That must have been a long tailed th350. Quote Link to comment Share on other sites More sharing options...
Guest aryanramsey Posted January 6, 2006 Share Posted January 6, 2006 i bought this transmission off of ebay,and im bringing it to a transmission shop, do i need to tell them what i will need to do or will they know.also the parts that the website mentioned would a transmission shop have those.and one more thing my car is an auto so would i need that lockup convertor you guys were talking about?it already has a convertor in it so anything would be of help. thanks http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=8019627835&sspagename=STRK%3AMEWN%3AIT Quote Link to comment Share on other sites More sharing options...
Greennovass Posted June 5, 2019 Share Posted June 5, 2019 How long does it take to do this conversion? Want to do it on a 64 chevy nova. Quote Link to comment Share on other sites More sharing options...
Miles Posted June 8, 2019 Share Posted June 8, 2019 (edited) edit Edited June 8, 2019 by Miles Quote Link to comment Share on other sites More sharing options...
Miles Posted June 8, 2019 Share Posted June 8, 2019 On 6/4/2019 at 5:18 PM, Greennovass said: How long does it take to do this conversion? Want to do it on a 64 chevy nova. This is a Z car site. You may want to visit a Chevy website. Quote Link to comment Share on other sites More sharing options...
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