Help with 700r4

[lookingtobuy]

Anybody put in a 700r4? Looking to update my 72. It has the 350 and
NP205. Whats involved and who would I got to if I need adapters.

Thanks in advance.

[cstanley]

i almost did it with my blazer. i wish i would have, but i didn't have the time or shop that would do it.

you'll need to go to advanced adapters http://www.advanceadapters.com/. some guys on the board have done it. also check the forums at coloradok5.com.

i think the 700 is 1-7/8" longer than the 350, but the adapter may take up the slack. otherwise, you might be shifting the t-case back or the engine forward.

[onetonk5]

buy the 700r4 and 205 i have for sale and its a bolt in.

[earl87gta]

there is a post int the 4x4 section on the convertion check it out there is a link to a post from a while back that gives you other options besides the advanced adaptors shaft.

[72sierragrande]

I installed a 700R4 in my 72 GMC 4X4 in place of the stock 350 trans.
The 700 bolts right up using the same stock adapeter the 350 uses. What you have to change is the out-put shaft on the trans. Advanced adapters make the shaft. The 700R4 is 2.25 inches longer then the 350 so i moved the motor mount cross member forward. This keeps the transfercase in the stock location. This work out vary good even with a big block. hope this helps

[Chris27]

I did a 700R4 in my (former) 72 K5. Advance Adapters output shaft for the tranny. Moved engine and tranny ahead 1 3/4". (700R4 is 1 3/4" longer than TH350). Stock t-case adapter bolts up to the new tranny. T-case remains in stock location and stock driveshafts can remain. Moving the engine ahead also gives more room for an HEI distributor. Stock column shifter was used with some "adjusting" . It's actually a pretty easy swap, and totally worth it.

[earl87gta]

you can also buy a spacer that goes inbetween the TC and trans I have used both and if I ever do it again it willbe the spacer the short shaft is 150 then you have to have a trany shop put it in it is just to much money when you can get a 50 spacer to do the same thing.

[Chris27]

you can also buy a spacer that goes inbetween the TC and trans I have used both and if I ever do it again it willbe the spacer the short shaft is 150 then you have to have a trany shop put it in it is just to much money when you can get a 50 spacer to do the same thing.

That would make the tranny transfer case pretty long, it may mean cu$tom Drive$aft$. If the tranny is getting rebuilt anyway, do it with the short output shaft.

[earl87gta]

I had a 6 in lift on my blazer when i did mine so I had longer shafts already but when I went to the 700r4 I did not have to change them again. it didnt add the much to it I moved the engine a head I wanted the extra room for the HEI distributer so my drive lines didnt move the much.

[JMac11]

Moved my engine forward, 700 input shaft can be machined down and shortened as there were plenty of spline material, but the outer diameter was not same diameter as you go further up the shaft. Basically, cut shaft 1.5" and make sure diameter is correct to compensate for new shorter length.

[jaros44sr]

So what are the advantages of the 700R? I'm new and stupid, pls. help..... J.

[Chris27]

So what are the advantages of the 700R? I'm new and stupid, pls. help..... J.

Overdrive fourth gear and a lower first gear = Lower highway Rpm & better low end grunt.

[jaros44sr]

Originally Posted by Chris27

Overdrive fourth gear and a lower first gear = Lower highway Rpm & better low end grunt.

Thank You, you have enlightened me, sensii

[smokekiki]

Originally Posted by Chris27

That would make the tranny transfer case pretty long, it may mean cu$tom Drive$aft$. If the tranny is getting rebuilt anyway, do it with the short output shaft.

Only if you move the transfer case.Putting in a spacer,and moving the engine and trans forward will not change the driveshafts.

[Chris27]

Only if you move the transfer case.Putting in a spacer,and moving the engine and trans forward will not change the driveshafts.

Can you move the engine that far ahead? 700R4 is already 1 3/4" longer than TH350. I'm guessing the spacer is 2" ? That would make the oil pan pretty close to the front diff. My engine moved ahead 1 3/4" was pretty close.
3 3/4" may be too much.

[earl87gta]

the spacer is only like 1 in thick. If you change to an electric fan you will have a ton of new space. you can split the difrenc any way move the engine a head an 11/2in and move drive line 11/2in and you wont have any trouble

[jaros44sr]

Thanks for the help guys, now I just have to find the 700R.

[71RestoRod]

IMO Earl's got it pegged. Best way to do it is w/ the spacer, engine forward and transfer case back. The AA shaft leaves you with the front CV really close to the pan on the 700R4. No way to use a deep pan. With the spacer, you have gobs of room and can run a deep pan. Even with the driveshaft mods it's still way cheeper then tearing down the 700R4 to install the AA output shaft.

[Chris27]

Either way will work. It comes down do personal preference, I guess. Just be sure to use a '87 up 700R4 and get a "K" case tranny. K case has the heavy duty cast aluminum inspection cover with mounts for the support rods.

[jaros44sr]

Looks like yous guys covered all the bases, thanks for the input. Invaluable information, think I got it strait. J.

[71RestoRod]

Originally Posted by Chris27

Just be sure to use a '87 up 700R4 and get a "K" case tranny. K case has the heavy duty cast aluminum inspection cover with mounts for the support rods.

Best advice yet... although the support rod mounts just seem to get in the way (at least they do with my G-body style headers).

With the electronic shift kits available now I don't know why a 4L60 wouldn't be a good option.

[ABLAZN]

With the electronic shift kits available now I don't know why a 4L60 wouldn't be a good option.

The stand alone computer systems run $1200 or more from the ones that I have found. Add that to the price of a 4L60-E and it become quites expensive verses just going the 700R4 route. If the price were a little better I would jump on it in a heartbeat. I have a 4L60-E sitting around that I gave a song and a dance for, and it still is just cheaper to do the 700R4 that is completely rebuilt and includes the price of the adapters.

[71RestoRod]

Originally Posted by ABLAZN

The stand alone computer systems run $1200 or more

Ouch. Now I know why not such a good option. I thought there were cheeper ones on the market now.

[earl87gta]

cheapest I have seen is around 700

[ABLAZN]

Originally Posted by earl87gta

cheapest I have seen is around 700

After my first post I went and looked again to see if there was anything new since the last time I looked. I too found a couple in that price range, but then there was another $150-$200 harness to buy after that.Plus one of those needed to be programed with a lap top. I also found a unit that GM Performance sells with everything for about $1100 IIRC. Regardless, not a cheap date to go this route. Still it has its appeal, and I may just hold on my 4L60-E until my cash flow gets better.