Blazer Overdrive 700R4 or 460LE

[mseymour]

Im seeking advice on installing and OD tranny in my 72 blazer. Im currently running a HO350 with carb, TH350 and NP205. Wanting to add an OD and not sure if 700r4 or 460le is the best route? Also looking for simplicity of installation. Ive searched the site and found lots of talk on 700 installs but cant find much for the comparison of the two into my particular applications. And I would prefer to slide the motor forward instead of moving cross members and cutting driveshafts

Any help and advice is much appreciated!

[SeventyOne]

4L60e is just an electronic version of the 700r4.

4L60e will need wiring and a computer/ecu to work. 700r4 needs a Throttle Valve cable attached to the carb throttle blade.

If you want simple I'd go 700r4, get it built with the proper output shaft from Advance Adapters to mate right up to your NP205 Tcase. Get a Bowtie Overdrives TV cable kit to handle that part.

You'll have to either move your engine forward or the trans/tcase back to accomodate the 700r4's increased length over the Th350. It's 1-7/8". I personally moved my engine forward. You can keep you existing driveshafts this way and it gives move clearance at the firewall for valve covers and the distributor.

Another option for Overdrive is to install a gear vendors OD unit on the end of the Tcase. I dont have much info on this but it is an option.

[Ptjsk]

Originally Posted by SeventyOne

4L60e is just an electronic version of the 700r4.

4L60e will need wiring and a computer/ecu to work. 700r4 needs a Throttle Valve cable attached to the carb throttle blade.

If you want simple I'd go 700r4, get it built with the proper output shaft from Advance Adapters to mate right up to your NP205 Tcase. Get a Bowtie Overdrives TV cable kit to handle that part.

You'll have to either move your engine forward or the trans/tcase back to accomodate the 700r4's increased length over the Th350. It's 1-7/8". I personally moved my engine forward. You can keep you existing driveshafts this way and it gives move clearance at the firewall for valve covers and the distributor.

Another option for Overdrive is to install a gear vendors OD unit on the end of the Tcase. I dont have much info on this but it is an option.

The gear vendors overdrive is a nice unit!

I installed it in my '72 Jimmy, and it performs extremely well.

As always, there's a ton of debate about the 700's and the 4L60's. The transmission shop I've went to for decades talked me out of going with either of these two transmissions.

He said the 350 was very strong and very durable.

So, I put in a GV (although skeptical by many), it worked out for my application perfectly.

Pat

[hemi43]

You will need to change the gear ratio if going overdrive especially with those tall tires.
Also, that engine will not be happy cruising at 2000 RPM especially if it has a cam in it.