Is it worth it ?
 

I have a 700R4 that I can put in my truck. My truck has a 396 and TH400 right now. I love the way my truck runs but would like better mileage and I know the 700R4 will increase my mileage especially on the highway.

Its going to cost about 800.00 to put the 700 in my truck and I was ready to do it then started to second guess myself..

I'm looking for opinions and pros and cons of the TH400 versus the 700R4 !!!!

Re: Is it worth it ?
 

It's win-win if the tranny is built to handle the bigblock. You get a Lower 1st gear (so quicker off the line) and then you get OD for highway cruizing. Just make sure it is built to handle the torque of the BBC and the TV cable is adujsted correctly.

Re: Is it worth it ?
 

You must also consider the rear end gear ratio. OD with a high geared rear can hurt mileage. Use something like Richmond gear calculator to see if the final drive ratio will yield better possible mileage. www.richmondgear.com

Re: Is it worth it ?
 

Boog beat me to it, and many simply don't believe this, but yes, an overdrive will not always help MPG, and can actually hurt it.

Re: Is it worth it ?
 

Thanks for the info. What do you mean by "handle the big block"? The 700 is from a 90 Burb that I wrecked. I have it documented that is only has 25,000 miles since a rebuild by alocal very reputable trans shop.. I dont race my truck but will occasionally drive aggressivley in traffic or pull away from a traffic light spiritedly.

Re: Is it worth it ?
 

he means the 700 isn't a very strong unit to begin with, and a big block is a torquey motor.

Re: Is it worth it ?
 

The 700R4 is a great tranny when built right! I had one built by a local shop near Sacramento A.T.O. and it cost me $2800 and is guarentied for 700HP but only out of a small block!!!! Big blocks just have to much torque through out the power band of a 700. You need to go to a 4L80 if you dont want to be left on the side of the road during those traffic runs! Just my $.02:)

Kevin
LFD Inc.

Re: Is it worth it ?
 

naaa, 4L80E is way too expensive to set up. A TH400 with a gear vendors would be better, and cheaper.
Heck, if your TH400 is a strong well maintianed unit, you could go a gear vendors for about 1200 or so... not a whole lot more than the 700 numbers listed here, and WAY stronger.


You'll NEVER break a gear vendors, plus, you'll have a 6 speed.

Re: Is it worth it ?
 

If you want a little sticker shock look at the prices for gear vendor. They have gone up a tad. Look at price code D

http://www.gearvendors.com/prices.html

Re: Is it worth it ?
 

You can find 'em on fleabay for about a grand used.

Re: Is it worth it ?
 

that is true, if you are looking for a 2wd setup, and have some fabrication skills, you can always find some aux. overdirve setups that would bolt to the rear of your TH400.....personally I would stick with your TH400 and throw a couple hundred at getting an aux. overdrive.....the cost of beefing up your stock 700R4 plus installation......you could buy a couple cases of beer and an aux. overdrive.....and possibly trick some local members into helping you with the install :smile:

Re: Is it worth it ?
 

I have a guy her in Calgary that is building my 700 for my 502 Ramjet the will handle all of the 585ft/lbs plus more. He will stand behind his work, as he builds many tranny's for local racers.

If you need his number, PM me.

Re: Is it worth it ?
 

Would I see better mileage on a diesel 2wd (2.76 or 3.08)with a 700r4(lock up converter) or a turbo 350 or 400?Also would a 6 speed manual from a latemodel f body bolt up and hold up to a N/A6.5? would a stock diesel flywheel work which clutch would i use f body or truck?
Thanks
Shane

Re: Is it worth it ?
 

with gearing that low, you'd probably be better off without the OD.

Re: Is it worth it ?
 

What gearing should I run?.......with 2.76s it would be running 150mph in overdrive at 3500rpm:crazy: with 235/75/15 tires
Shane

Re: Is it worth it ?
 

If you want to run an OD tranny (IMO) you should have a rearend with at least a gear in the 3.40's and if you do any towing or hauling a 3.73 would be best. A lot of new trucks with OD run 3.73's. My z71 has a 3.73 locking rear:) Cars can run the higher gears, because they're more aerodynamic, weigh a lot less and run smaller tallers (effectively giving them a "lower" gear in the end.)

Re: Is it worth it ?
 

Thanks everyone for the thoughts. ideas and opinions on my transmission dilema. I think for now I'll take my TH400 get it checked out and serviced and use it for the time being. I'll tuck the 700 away in a corner of the garage (cause they dont deteriorate from sitting) and spend the 800.00 I was gonna spend on the trans swap on my lowered suspension..