Depends on whether you want computer control or not. The 700 doesn't need a computer to shift the trans or lock it. The 4L60E needs a computer. They make stand alone computers for this purpose.

Keith

 

No, I really don't need computer control. Would be nice, but not really necessary for me.

Right now, either one would work for me in my application 300-400-500HP street. sees 50-85MPH regularly and in city driving.

 

700R4 is a 4 speed version of your 350. A very good unit and with some minor upgrades it will last you a long time.
First, you need to be sure that you can add the trans downshift cable to your carb. If you can get the bracket off the donor it will make it easier. The cable is self adjusting if you follow the directions for the donor vehicle too.
Upgrades I would absolutely do before installing are a deeper pan to hold more fluid, preferably with a magnetic drain plug. Be sure to install the spacer for the filter so it can pick up off the bottom of the pan.
Next I would either bypass the radiator trans cooler all together or run inline with a PLATE AND TUBE trans cooler. DO NOT get one of the tubes with the foil fins on it, they aren't nearly as efficient. Get the biggest one you can find. My 85 K-10 has one for a 26,000 pound truck that I grabbed at a chain store for less than $50.
Lastly, since you are going all out here, add a temp sensor and gauge to the OUTPUT line from the trans to the cooler. This way you are getting a true reading for the fluid in the trans. If you can find a deep pan with the port, install the sensor there. If the fluid ever gets above 260*, change it asap!
How did I learn all this? Why, I blew up my plow rig of course! Now I have a rebuilt trans and all of the trimmings. I have plowed 4 years with it and had not a hiccup since. Good luck!

 

A 700R4 is not a 4 speed version of the 350.They have different gear ratios than each other & many other differences.They are more different than they are alike except for diminsions.The 4L60 & 700R4 are the same trans,just a different #.GM changed the name in 92 from 700R4 to 4L60.The 4L60E was introduced in light trucks in 93,cars in 94 & is basically the same trans as the 700R4/4L60 except it is electronically controlled.That cable you speak of,is not a kickdown cable.It's a throttlevalve cable(TV cable) that controls line psi,shifting.It is not self adjusting.Improper adjustment will kill the trans very quickly.

 

. All three the same tranny, 700-4R, 4L60, 4L60e other than the 'e' requiring computer control... 'e' 's started about 1992 I think...

. Some of the non-'e's use speedometer cable and some use a sensor for electronic speedo...

 

Ok, Yeah that's what i read.. 1992.

I can use either speedo. Am going with Autometer Ultralite.

I've heard the 700R4 is popular with rodders.

Oh I also have a 3 or 4 speed saginaw I tried to describe elsewhere with a broken tooth.

 

You'll hear all kinds of horror stories about the 700 but if it's built properly it will hold up just fine for street use. I put one behind an '88 Chevy 1 ton 454 and it worked great......BIG improvement over the granny 4 spd it replaced. If you're going to run really big power then the 4L80 would be the trans to use.

 

If you're going to run really big power then the 4L80 would be the trans to use.

. GM 8L90 available now...

. Jeep Cherokees and Chrysler 200's using a 9-speed auto now...

 

300-500HP is my target.

 

Ive got 11 tranny coolers for 7.3 diesels, i give them away, i always replace them due to a tranny failure, and spend some time cleaning the old ones, and throw them im my cabinet. Plus they have mounting tabs on them already that work great

 

Trans coolers? well Dad had one on the Lincoln. I'm not totally against using one.

 

If you're using anything other than a near stock cam then there is a good reason to go 4l60e. It took me 2 years of work here and there to get the governor setup right and to the point where my 700R4 upshifts and downshifts the right way for my cam. I must have taken the governor in and out 40 times. Each time it dribbles a little fluid and I get dirt in my eye. Sucha' pain. If I had used a 4l60E, it could have been programed with the right shift points in a few hours.

 

Yeah, the cam will be a bit different than stock. Still have not decided which one it will be but..

Update: sold the TH350 today.

What I have been seeing is a lot of 4L60E's on the LS1 engine. Youtube seems to have a lot of that combo on there too. The one I really liked had a Flowmaster 40.