Trans vs rear end
 

I'll be home soon and wanted to know you thoughts. Do a 700r install or gears for the rear for better highway speed. Not looking to hot rod just want to cruse at 65 without being tached out. 700r would cost alot more to do than the rear end but has better top end without the gear change. But i could do the 5 lug conversion and get posi with lower gears(3:08s maybe??) for alot cheaper.Its on my 66 SWB. So spend the dollors on the 700r or just do the rear end and use the rest else where???? It has 3:73/6 lug right now and a 350/350. Thanks for your thoughts..

Re: Trans vs rear end
 

I have a 64 c-10. I bought a five speed manual transmission out of a s-10. This way I have overdrive for highway speeds, and I still have the torque in the low gears. I changed my engine out to a 350 V-8. If you are going to use the s-10 transmission, get one that is attached to the 4.3L engine. This is an easy match to a 350. I do not like the 700R4 due to it not being a strong transmission. Once you get over 300 hp, you will tear that transmission up.

Re: Trans vs rear end
 

I'm changing out my 3:73 for a set of 3:08's my 350 turbo does fine and works great behind my 350. I'm also staying with the 6 lugs. I found a place here in Iowa that sells ring gear and pinions for my 12 bolt at the price of $165.00 and the master install kit for $95.00 thats the cheapest I've seen. WWW.uspowertrain.com

Re: Trans vs rear end
 

From what I understand the carrier must also be changed out to accept the 3:08 gears. But there is a shop in town that does nothing but rear ends and for 1200 I get all new bearing, seals, posi (<-- biggest expense) and gears. They also clean and repaint the housing. Add 300 bucks for the 5 lug axels from CPP. Up to 1500 for a rear end where I’m looking at around 2000 for a 700r swap before I even get a drive shaft..

Re: Trans vs rear end
 

apachedaddy, here's my 2 cents. the 700r has a final drive ratio of .7, right? that gives 3.73 x .7 = 2.61, which gives a lower hiway rpm than the 3.07 AND still gives better acceleration (and I'm not talking drag racing here, just spirited, normal, I like the sound of my dual pipes, around town driving). Remember, you don't have to drive in OD all the time, in Drive (3rd) you are 1 to 1, and you can drive all day in that gear if you want. Lots of guys like the 3.73/700r combo. I have the 3.07/700r combo with a manual lockup.

You don't HAVE to spend $2000 to put a 700r in, even with the driveshaft.

Future plans factor in here also as to 5 lug vrs 6 lug all around. If you don't have them already, the extra (?) $ are well spend on power steering and power disc brakes.

Re: Trans vs rear end
 

I didn't know that you needed to change the carrier to change the ring gear and pinion! I'll have to check into that,could drive up the cost. Most of our driving with our 64 is highway and I'll never tow with it so 3:08 will work fine with us. I can buy a rebuilt 700R4 from a tranny shop with warranty for $1500.00 but I would have to get a new floor shifter and shorten my driveshaft.

Re: Trans vs rear end
 

That's what my research has indicated

Re: Trans vs rear end
 

back from deployment?

Re: Trans vs rear end
 

Is it different with a posi and open rear end?

Re: Trans vs rear end
 

don't think so, I think what has been referred to on past threads as "the carrier" may in fact be the "case", i.e., that which the ring gear attaches to. If thats so, then upgrading to a posi should automatically take care of the problem as you'll be matching it with the new ring gear, if however, you already have the posi then the new ring gear diameter wont work. that is my understanding but, I've misunderstood many times before

Re: Trans vs rear end
 

i'll vote with fleetsidelarry - you get the best of both worlds with the 700r4. decent 1st gear for acceleration and BETTER mileage/lower rpm at whatever highway cruising speed you happen to be at. 700r4.

But I will admit, I have a similar problem, a 3.73 with the desire to put in either a tremec or a 700r4... either way, I will then easily smoke the tires in 1st... not exactly something I'm looking for on this build. I'm a bug fan of tremec/700r4 and 3.42 gearing together. But now that doesn't help your choice dilemma at all does it...

In the end, I'm going to choose based on desired highway cruising rpm - so I will be going with the trans swap 1st.

Re: Trans vs rear end
 

and I agree with Jocko about doing the tranny first. I first swapped out my 3.73 for a 3.07 because it was easy and cheap (complete rearend from a donor) and still wasn't entirely happy with cruisin' rpm. after changing the 400TH to a 700r4 with a manual lockup, I'm very happy. For my style of driving I needed both.

There are calculators online that'll let you play with gear ratios, mph and rpm, might be worth playing with to put you in the ballpark.

Re: Trans vs rear end
 

i was under the same circumstances/dilemma....i currently have the stock 6-lug with 3.73 gears and a 2-spd Powerglide trans....i had already decided that i want to switch to 5-lug...i really didn't wanna throw that much $$$ at a 700R right now, since i have other things i'd rather fix first...nothing wrong with my Powerglide, so i just decided to look for a '71-'72 rear with 3.08's as a direct swap....luckily i came across a '72 parts truck locally for sale on Craigslist that had the rear end i wanted...another board member/friend was interested in the '72 cab, so we went in together & purchased the truck...the '72 rear is now out & being freshened up/cleaned/painted by my dad and I....after it is installed, i then have access to the disc brake front suspension from the '72, which will be rebuilt & swapped onto my '66 as well

as of now, i have about $140 into the rear end swap (new seals, diff. gasket, gear oil, wheel cylinders, shoes, drums)....and i'm looking forward to being able to cruise the highway & not get run over, :lol:

Re: Trans vs rear end
 

Well, my first question is, do you have a 4 spd with the granny low, an auto, or a 3 speed?

If you have the sm420, a 3.08 rear works quite well. I have 3.08 gears in my k1500 and with a 30-ish inch tire can cruise at just over 2000 rpms at about 65. With that tall a rear gear the granny low is useful though.

Re: Trans vs rear end
 

likaroc13, your suspension set up will be the same as I have, you'll like it (esp if you get power steering also), however, like I said, I wasn't completely happy with just the 3.07 (or 3.08, whatever people want to call em). Just to clarify, when I say highway cruising I mean Interstate (I-95 around here) which means around 75 mph, for State highways (55 mph) the rear end would have been enough.

Davetopay, you bring another factor into the equation which is tire diameter, your tires are a couple of inches taller than my 275/60/15's. The calculators I mentioned earlier do factor tire size in. With a tall gear and tall tires it helps to have the granny OR an automatic. I believe Apachedaddy has a 350 auto currently.

Re: Trans vs rear end
 

My truck is a 1960 GMC which came stock with a Dana 44 and optional 3.90 gears. I swapped out the V6 and granny 4 speed for a 350/350. Subsequently this became my 70 mile (round trip) daily commuter, so I had 3.08’s installed. Not sure about Chevy rear axles, but on the Dana the 3.70/3.73 ratio is the break point on carriers. Anything 3.70 and above (numerically) uses one carrier, and anything lower (3.23, 3.08, etc requires the other carrier.

I had mine done at a shop that specialized in 4x4 gear swaps, and they swapped my 3.90 carrier and gears for good used 3.08 components at a total cost of $250 including labor. I ran this combination for about 15 years, until I swapped in a Richmond manual 4 speed. My commute was generally at 50-55 mph, and with the 350/350 & 3.08’s, I averaged about 15 mpg. Not as good as overdrive, but a whole lot cheaper to put together.

After I swapped in a 1975 front suspension, I simply had the rear axles redrilled to 5 lug pattern at a cost of about $150, and installed the later 5 lug factory drums. Prices may a bit higher in different locations, but this still seems like a viable alternative to those on a limited budget.

Re: Trans vs rear end
 

yeah, i'll be adding power steering/power brakes in the near future as well...and when i say highway, i mean Interstate as well...i'm not looking to run with the modern technology, but i wanna be able to keep up somewhat...and yes, tire size will also need to be factored in.... i'm currently running a 205/75/15 tire

by the way, mine is NOT a daily driver either...just a weekend cruiser or show n' go

Re: Trans vs rear end
 

Yes, I should be home the first part of Nov from Afghanistan. Fun filled 13 month deployment.

Well it sounds like the 700r would be the better choice. The only reason i say 2000 for the trans is because I can only do internet searches for things right now. I'll go and talk with some local trans shops when i hit the ground and see if I can find a better deal. Or maybe find one at the local PNP but from what i read a stock trans may not hold up very long if you start to tow or beat on it a little.

One last question, I want to buy the CPP motor mounts. If i put them in the foward holes on the frame would this move the trans up enough to make up for the longer 700r??? And yes i have a 350/350 combo in the truck now.

Thanks for all the info

Re: Trans vs rear end
 

friend of mine ran a used 700r for a couple of years behind his 454 in a 63 suburban (which is about 1000 lbs heavier than our trucks) before it broke. if you go that route, there is a year/model break you want to look for (I can't remember what it is off the top of my head). my motor mounts (clam-shell type) are in the forward position but it only gives about an inch more clearance, which is great for the HEI and bellhousing clearance but not enough for compensate for the 700r's extra 3 inch length.

I'm about 50 miles from Pooler down 17.

Take care

Re: Trans vs rear end
 

Okay,I'm wrong I found out at my local Speed shop I have to buy a new carrier,my cost on a new possi unit is$595.00-ring gear and pinion $175.00 master install kit $95.00 Labor to change it out $300.0= $1165.00 I found a 700r4 with 2 year warranty and shift kit installed for $1295.00 I think trans will be most cost effective even with having to shorten driveshaft and buying new floor shifter

Re: Trans vs rear end
 

[QUOTE=Indian113;4165438 I found a 700r4 with 2 year warranty and shift kit installed for $1295.00 I think trans will be most cost effective even with having to shorten driveshaft and buying new floor shifter[/QUOTE]

does the cost include a new torque converter? also, you need some way to control the lock-up, but there are simple cost effective ways to do that.

Re: Trans vs rear end
 

Thats why I said around 2 grand for the trans route. There are little things that add up quick to do the full install.

I did all my shopping through "Bowtie Overdrive"

175 = Converter
160 = TV cable system
100 = Lock up kit
70 = Speedo kit
38 = converter cover
50= flex plate
35= dip stick

1095 = Stage one trans
1295 = Stage two trans

They also havs a trans cross member for 175, its built so you dont have to do any mods to the e-brake cable.

There are other places that have kits like "Monster trans" for right at 1900 but you still need a flex plate.

There is also the drive shaft factor and thats around 300 to have one built and shipped.

There is allways the craigs list or P-N-P route that i'll look into once I'm home but I'm one that says you get what you Pay for in the long run.

Re: Trans vs rear end
 

http://www.gearvendors.com/cgi-bin/s....y=7&submit=GO

Pricey but well worth it (if you want to keep the Granny gear)!

Overdrive final ratio is the same as having a 2.77:1 rear gear set.

Re: Trans vs rear end