Help for a fellow member

[gchemist]

Hey, gang I'm from the 73-87 truck forum. I received the following message from a board member. I can only answer a few questions because I'm more familiar with the 73-87 trucks. The 67-72 trucks are just a little different. Can y'all help me answer his questions? You can guys can do a better job and I can. Thanks
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Hello,

I was reading some of your posts on the chevy board about 700R transmissions. When I looked at your profile and saw that you lived in TX I had to ask you a couple of questions (HEHEHE!!) about installing one of these transmissions in my truck. I have a 70 Chevy SWB truck with a 250 six and 3 on the column. I am going to put a 327 motor in it. My questions are as follows:

1. I have a truck tilt auto column and how do you know what gear you are in (Except by feel) and will it work with a 700R?

2. Will I have to move the trans mount and will a standard auto trans mount from 67-72 work?

3. Will the drive shaft have to be shortend/legthened.

4. Will a T350 yoke work with it.

5. Have you heard of a hydraulic kit to lock up the converter and know if this is a good idea.

6. I have heard that Lokar makes a good cable and accessories for these transmissions. What did you need to buy to get the linkage and everything to work.

7. Who rebuilt your transmission so I can get them to do mine. I have heard that some year models of this transmission are sturdier. Which year should I look for.

I know this is a lot to ask so you don't really have to respond but I am at the very beginning of my quest to get decent gas mileage out of the truck. Any additional info or suggestions you could give me would be greatly appreciated.

Thanks,
smonty

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Gerardo
1983 Custom Truck
TX Plates: "BAD BOW"

[frogsmakr]

I think the answers are at www.700r4.com

[Fast68Chevy]

th350/400 crossmember 67-72 is the memeber to use, th350 yoke is same and stock column will work fine, you dont need to go all the way down to L1 anyways, it may anyways if you enlarge the shifter lever slot in the end of the column

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-71/C-10(thx teeitup and crews!)350 4+4/CH465(thx 71Chev, GMCPaul, and CPNE)longfleet bed(thnx meathead95)!still building it-
-'84 Z28(Z28) 1G1AP87GXEL100000 with H.O. 305/4bbl/190net/hp(L69) 3.73 rear(GT4/YC4) 700R4(MD8-MXO) & other goodies
-79 G20 pass van, 350/th350/10bolt,
paint is overrated
Randy- Lincoln, IL

r68c30@hotmail.com
© RSS Enterprises 2000

[red71cheyenne]

I think Fast covered all of it, but just in case: the crossmember just has to be moved back down the frame a couple of inches, drill new holes. The drive shaft will have to be shortened and its easy to go to a on piece. Good luck, and make sure you have the tranny checked before you install it. Taking it out again after only 600 miles sucks. Jeff.

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1971 Cheyenne C-10 w/700R4 and Tuned Port Injection
1969 K5 Blazer New project
1995 K1500 Sub(Mommas car)
1989 VW Golf(Beater)
Will be the daughters car if she will pay her insurance! Ha!

[67Blacksheep]

Chemist,
Many of Gerardo's questions probably aren't going to be the answers he is looking for. I am pretty sure the standard mount won't work where it's currently at. He will have to change his column if he wants to shift from there. ( Cheaper in the long run to mount a floor shifter). He may have to have a yoke machined, and the drive shaft will most likely have to be swapped. It may be much easier for him to look into a 400 or 350 turbo with overdrive, mount the shifter on the floor, and match up his drive shaft. I had a new yoak machined a couple years ago and it was only about $75.00. I was told years ago that standards had taller tunnels than the automatics, shouldn't cause any problems for him, but he may encounter extra space?? Anyway...best of luck to him.

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67 Chevy C20 LB Stepside,
350 4-bolt with goodies.

[This message has been edited by 67Blacksheep (edited March 24, 2002).]

[67Blacksheep]

Fast-
If he tried to extend the notch on his column, and cut a bit too much wouldn't he run the risk of possibly damaging the trans end??? I ran into the same with my column. A previous owner must have done the cutting, but I never could remedy it to work right. I ended up with it on the floor.

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67 Chevy C20 LB Stepside,
350 4-bolt with goodies.

[Fast68Chevy]

350 or 400 with o/d ? eh ?
only 4 speed turcks and 4x4 trucks had the taller bolt-in style transmission floor pans

yoke requires no machining, simpley cut shaft tube shorter and reweld the yoke back on and install U joints and then have the shaft assembly balanced and then instlal the shaft, and its free to elongate the sliot in the end of the column for the shift range finger lever, but who needs L1 anyways... the tranny shift shaft is only gonna turn so far, you can feel it go into the range, there are detent teeth on the range cam under the pan of the tranny, there wouldnt be any reason to move it any further down past L1 anyways.

good luck

[This message has been edited by Fast68Chevy (edited March 24, 2002).]

[smonty]

Wow! This is good info. It sounds like it might be easier to get a 350/400 with an overdrive. I have never heard of such an animal. Where would you get one and how much? Is this a modification to a stock transmission? This is important as I commute 130 miles a day and gas cost is killing me. Don't want to have to break out the old 86 Chevy (Toyota) Nova. I could enjoy my commute instead of dreading it everyday. Two hours of cruising in my truck sounds mo betta!

As it stands now I will have a modest 300 horse 327 and a 307 rear axle for sure. With an overdrive of some sort I should be at least in the 18mpg range hopefully. I have heard that some people have been getting over 20mpg.

Any suggestions are appreciated.

Thanks for all of your input.

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70 SWB STP C-10 327/350
70 Suburban 327/350
68 SWB Flt 327/Powerglide
68 SWB Flt 307/350

[Longhorn Man]

look into a 400 or 350 turbo with overdrive

There is NO SUCH THING.
Fast, you left out big blocks having the high hump too. And I have yet to confirm this, but my TH400 V-6 (305) has a factory high hump too for some reason. I'm thinking it was in all the V-6 trucks...but not confirmed though.
No reason to have a yolk machined...there are millions of TH350 style yolks being thrown around junk yards every day. Get one that is still in the tranny. (no rust on the smooth part)
As for your lockup..there are kits you can buy, electric ones, but from what I understand, all you need is a toggle swithc. However, if you go that route, it will stay engaged till you turn off the switch, and that means you'll stall it on a panic stop, or if you forget to hit the switch on the off ramp. Talk to a local tranny shop on advice for that.
Something no one has mentioned, is the speedo cable. The O/D tranny has an electricly driven speed, verses the mechanical one on the old tranny. Some one, some where makes an adapter. I seen one, I just can not remember where. Again, you may want to talk to a local pro tranny guy.
Another thing not mentioned is the T.V. cable. This is MUCh more touchey than a kick down cable on the TH350. This cable controles the fluid pressure in the tranny. If you leave it totally disconnected, it will shift WAY hard and wind out too much, it will also die in short time. If it is not adjusted just right, it will also kill itself in 20,000 miles,a nd with no warning. This is a very tempermental tranny, and does not like non-stock aplications.
How ever it ends up going in, go to a pro, and have them check the work, esp the d@mn T.V. cable adjustment. Make sure they check it with a hyd pressure guage for perfection.

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'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
Need to pick up the one ton Longhorn with a PONTIAC 350/350soon.
Thanks every one!
Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

[67Blacksheep]

Smonty-
I guess I owe you an apology. When I answered I was talking to a friend on the phone who I used to consider reliable. He swore there was such an animal as a 400 w/overdive. I was trying to help. I checked it out afterwards in Jegs and Summit, Then saw the reply from Longhorn to confirm it. If these guys say it's not available....I'd put my money on them. Sorry Bro.

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67 Chevy C20 LB Stepside,
350 4-bolt with goodies.

[gchemist]

Okay my spill time.

The 350TH/400TH OD units in poor man's terms is a locking torque conveter. No gear just a locking torque converter. The 700R4 is a gear OD unit and a poor mans "5th gear" is a locking torque converter. The 700R4 is nearly identical to the 400TH in size. The 700R4 can be rebuilt to take a beating. I have one in my truck that is built for 450+ HP.
smonty,
The builder I have is works from a small down outside of Austin. Since you live in Dallas I know a few board members that can probably recommend a good shop up there. I know guy who just put a panel truck on a 84 (?) 4X4 frame and had a 700R4 built for it.

Adding a 700R4 to your truck is worth the effort. I would want to drive the truck to work too. I just love seeing good old running trucks on the road. I don't own a 67-72 truck but here is what I would do. Change the column to an automatic type. Unless you plan on drive it at the track the only gears you need are R-N-D-3-2. The first is not necessary but sure is fun. The TV cable is no problem when you know how to adjust it. A good TV bracket cable will cure a lot of problems. The locking torque converter is not a problem either. You can buy a kit to take advantage of a locking torque conveter. If it does not lock you only loose about 200-300 RPMs. An external tranny oil cooler is recommended for a locking and nonlocking torque converter. The locking kit is usually tied to your brake switch. Hit the brakes and torque converter unlocks. The conveter will lockup again once you reach its stall speed of say 1800+ for such a heavy truck. The wiring kits are available from www.jegs.com www.summitracing.com and www.painlesswiring.com

A long tail shaft 350TH tranny drive shaft should be just about the right size. It's important to have the driveshaft balanced for the 700R4. The shaft will be turning some high RPMs so it should be balanced to reduce vibrations and destroying some U joints.

I cruise at 70 MPH with only 1950 RPMS with a 3.08 rearend. Better than close to 3000 RPMS with your setup. Save a lotta gas too!! That high reving 327 will love the 700R4.

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Gerardo
1983 Custom Truck
TX Plates: "BAD BOW"