Give me the really big picture on manual trans options

[zac]

I’m starting what is probably a fairly long process on getting my ‘70 K10 suburban up to “really nice stockish driver” condition. Nothing more than that. Standard 465/205 with 350 and 3.08’s. I know you guys are more into offroad stuff, but the depth of knowledge on this board is amazing.

Want to use this truck in retirement for low key, long-range travel, we spend most of our time on backroads, but obviously you have to go on interstates sometimes. Overdrive would be great, but swapping to a 700R4 seems like a total cop out. I am aware of the NV4500 option. I’ve also seen the a833 option, etc. My thinking right now is just build the best low-end torque 350 I can and then rebuild the stock 465/205 and call it good. The 465 is a pain on the road, but it’s time-tested and I’ve been driving them since the 70s. Modifications, fabrication and expense don’t bother me, but it needs to be worth it.

Thanks in advance!

[Matt Man]

The sm465 is essentially a dump truck transmission and shifts like one. It is bulletproof and easy to rebuild. I would put a gear vendors overdrive and keep the sm465. The nv4500 is a much more modern heavy duty transmission but can be costly to build and attain. I know the gear vendors isn't cheap but I think it would have a cool retrospect to it.

[1976gmc20]

You just have to learn to be a truck driver

I've had various pickups and trucks with the 420 and 465 and never had any issues driving either one of them (well, except the log truck really needed more gears - or more truck!).

I did have a 1980 K-10 with really tall gear ratios so high gear was almost an overdrive. You had to be 30-35 mph to get into high gear. It got 15 mpg at 80 mph, and 18 mpg at then legal 55 mph. You can do something similar with taller tires.

[Getter-Done]

What about this Option in the link below?
It will move your transmission shifter location
to the rear of the cab 7 1/2 inches.
So there would be some (modification) required.
(Bucket Seats? maybe) or a seriously modified shifter.
Maybe even a Custom bench seat.

Link:https://www.advanceadapters.com/prod...ex/#top-review







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[kipps]

In this thread, I've seen both Advance Adapters and Gear Vendors mentioned as possible overdrives for a sm465. Per my limited research which could still be in error...

Advance Adapters is very much an old-school style, which is perfect if you're going for period correct or retro flavored. It's shifted by a lever through the floorboard, giving you a twin stick transmission. It goes between the bellhousing and the transmission, requiring you to relocate the main shift lever and resize both driveshafts.

Here's a video of the Advance Adapters unit on a test-drive. It's installed in a F-150, but the stock Ford transmission is almost identical in function and form to the sm465.

Gear Vendors mounts on the rear output of the transfer case, and is shifted electrically. Since it doesn't relocate the transmission, the main shift lever remains in the same place. A button is added to the shift lever to operate the overdrive unit. Since this is on the rear tailshaft only, it can't be used while in 4x4. Being electrically operated, it should be easy to add a lockout while in four wheel drive. Only the rear driveshaft would have to be resized.

I found this video of the Gear Vendors unit. Around minute seven, he crawls under the truck('86 K10) to look at the installed overdrive unit. I don't like how low the oil pan hangs, or how much cantilevered weight is behind the transmission crossmember.

I'd suggest using a AA unit for 4x4 applications, and a GV for highway cruising. Since you're doing both, you will need to compromise somewhere.

Personally, I'd pick the AA overdrive, mostly for the old-school simplicity, the "cool factor" of a twin-stick, and the lower price. This would be predicated on my ability to keep a stock bench seat. There's no way I'd go with buckets.

One more theoretical option, is a twin sm465 setup. This has been proposed numerous times, and it's rumored to have actually been done. Somebody on pirate4x4(i think) was designing some adapter plates for sale, but they appeared to have dropped out of the game.

[zac]

I'm posting a pic of the room I have to work with. Not much. 7 inches puts the transfer case stick under the seat, and the other stick would be hitting the seat in 2nd, 4th and reverse. My wife would never sign off on bucket seats.

I've never looked at the Gear Vendors stuff that closely, but it's interesting. Most of my driving would be on the road and alterations seem minimal other than the rear driveshaft. Looks like $3100 or so. Whats a ballpark for a NV4500 swap if you do it yourself?

I've looked over all of your work with the NV4500 pretty closely here, just seems like a little farther than I want to go trying to keep my truck close to original. It's just not what I would call a bolt in operation, obviously.

I guess if there was some internal mod for the 465 you guys would have figured it out decades ago. The problem I have with our hills in KY is I need my gears to be 2, 3, 3-1/2 and 4. There's never a right gear for doing a tight turn and then going up a big hill. Full disclosure: the engines I've had in this truck have been crap. Getting that right first is the priority, I'm sure that will help a lot.

[Getter-Done]

Good research kipps.

I have been looking at different options
just like zac .

zac
With your Suburban/ the seat could
always be easily moved back.

Here is a thread link below
from about 6 months ago
That started my research into
this option.

Link:http://67-72chevytrucks.com/vboard/s...d.php?t=777476






.

[1976gmc20]

I still say the simpler option is just go to higher axle ratios or substantially taller tires.

The 465 still has plenty of lower gear options

Or just drive about 65 or so in the right lane and let everybody go around. You could finance several months of travel on transmission swaps and overdrives.

[kipps]

Zac, the main transmission stick will obviously have to be rebent. I think everyone who installs the AA overdrive does redesign their shift lever to move the head back in the correct spot.

On a squarebody with a np208, the transfer case lever is cab mounted, with an adjustable link connecting to the t-case itself. I don't know if such could be fabbed up for your application.

As far as the nv4500, that's the closest to a drop in replacement. I don't know about the earlier trucks with the np205's, but I've looked into it a little for my truck.

The np208 will bolt up to the back end of any chevy nv4500(somebody please correct this if I'm wrong). The nv4500 is practically a drop-in replacement for a sm465 in the case of a later model squarebody. I've heard conflicting reports about the length of the nv4500. Some folks say they're much longer than a sm465, and others say they're within spittin' distance in the 4wd configuration, and don't even need driveshaft modification.

To buy a craigslist nv4500, you're doing really good to get it for under $1200. And that's not rebuilt or with any history. You could potentially get into one for cheaper, if you buy a 2wd unit and convert it. Rebuild kit for $300, new output shaft and rear housing for $300, and possible transmission cost of $400.

[mongocanfly]

I'd have to agree with using tire size or axle ratios to solve your issues...after you optimize your engine...
Much easier to keep your current driveline intact... I drove a sm465 for yrs and never had any issues
But....
If you wanted the best of the best and wernt worried about the cost...I'd say nv4500...but they aint cheap..I've got 2 and love em though...but justifying cost of one is tuff ..
If you went divorced transfer case, you could use any trans you desired...with a burb,youd have plenty of room for one

[zac]

I considered the divorced option back when I pulled a full synchro T19 close ratio out of a 2wd (?) Scout I had briefly. Thing shifted like a dream, but the swap was beyond impractical. Of course, if a guy really wants something that shifts like a car, he could go drive a car. That’s not why I’m here.

I’ve done stuff like stick bending, and I was “modifying” stuff back when nobody had heard of a plasma cutter. We used cutting torches. I’m really trying to keep heavy mods to a minimum here. I’m keeping in mind this is a 50 year old original 4wd burb. I was hoping there was some “silver bullet” here I hadn’t run across.

Even with my bad engine right now with 3.08s and 31’s I can generally do 70 on the interstate. Maybe not always uphill. I have no qualms about hanging in the right lane and letting people give me a thumbs up—or middle finger—as they blow by. Based on all your input so far I’m still thinking of just rebuilding the original drivetrain, and if somehow it gets to where I have so much money sitting around the house that I’m tripping over it I can look at that Gear Vendors unit.

[Getter-Done]

zac
You started a Great Thread.
I want a Gear-Vendors also (Once I win the Lotto).
Advance adapters is probably what I will use.
Because my truck is 2wd.
Some of the members with 4 wheel drives
will have some good input on this subject.






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[kipps]

Keep in mind that fuel savings won't pay for an overdrive unit.

Assuming $4000 installed cost, $3.00 gas, and raising your mpg's from 11 to 14.

.273 cost per mile at 11 mpg.

.214 cost per mile at 14 mpg.

With a savings of about six cents per mile, you'll need 67,000 miles to pay back the purchase price.

I'm not saying don't do it; just don't think of it as a cost-saving measure. Only pursue this if you personally want the extra gears.

Also, if your wife is handy with a calculator, don't use mpg gains to convince her of the purchase.

P.S. Just in case math is not your idea of fun-- To get the cost per mile, divide 1 by the mpg to get gallons per mile. For example, 1 divided by 11 results in .09 gallons per mile. Multiply that number by the cost of gas($3.00), and you get 27 cents per mile.

[SunSoaked]

Originally Posted by zac

I’m starting what is probably a fairly long process on getting my ‘70 K10 suburban up to “really nice stockish driver” condition. Nothing more than that. Standard 465/205 with 350 and 3.08’s. I know you guys are more into offroad stuff, but the depth of knowledge on this board is amazing.

Want to use this truck in retirement for low key, long-range travel, we spend most of our time on backroads, but obviously you have to go on interstates sometimes. Overdrive would be great, but swapping to a 700R4 seems like a total cop out. I am aware of the NV4500 option. I’ve also seen the a833 option, etc. My thinking right now is just build the best low-end torque 350 I can and then rebuild the stock 465/205 and call it good. The 465 is a pain on the road, but it’s time-tested and I’ve been driving them since the 70s. Modifications, fabrication and expense don’t bother me, but it needs to be worth it.

Thanks in advance!

Is there a question in there?

[1976gmc20]

Just remember, folks drove all over the country in those trucks when they were brand new

[Mike C]

I would look to build a torque monster motor. 383 or 406 with a cam that had something in the 210-214 degrees at .050 and then tailor the final drive ratio to the tire height to get something in the effective 2.80 range. This combined with the 465 should make for a great setup even on the highway up to 75 mph. And it's cheaper to build the motor than do an NV4500 swap without any of the interior mods needed for shifters etc.

[61K10]

no cheap way to do what you want. The 7" splitter would get you your 3 1/2 gear. 1/2 in all gears. Install a twin shifter t/f case set up, re-bend 465 shifter. with a 383 eng.

[whtgmc68]

A NV4500 swap is very pricey. Five years ago I paid $3,100 for a new Dodge NV4500 with a GM input and a rebuilt Dodge NP205 that I put in my 68. With the necessary bellhousing and clutch components, it was a $4,000 swap. This configuration was only about an inch longer than the SM465/NP205 combo that it replaced.

I have a fairly thirsty 383 and it will get about 15 MPG when driving two lane roads at about 60 mph. I consider this pretty good mileage for a 400 HP engine, 35" tires, 4.56 gears and 1-ton axles. The engine turns about 2000 RPM @ 60 mph and about 2700 @ 80 but I do very little interstate driving.

All in all, I can't say it is cost effective but it is a discussion point with someone every time I drive the truck and if the lower revs help keep the engine around longer, I am OK with the expense.

[kipps]

Originally Posted by whtgmc68

...it will get about 15 MPG when driving two lane roads at about 60 mph...

That's very good mileage! I sure wouldn't be complaining.

With my old TBI 350, running around on the farm, I was getting 7 mpg. I'm hoping for 13-ish under the same conditions, once this LS swap is done.

[whtgmc68]

[QUOTE=kipps;8550932]That's very good mileage! I sure wouldn't be complaining.

I have to baby it to get those figures. 8-10 MPG is usually what I get because I don't seem to have enough self control to keep my foot out of it!

[b454rat]

Old truck I built had a 454, 4-speed, 4.10s and 35s. Would do 70 no problem without bottoming out the tach. Prolly cause of the 454, but was a blast to drive. Never got old shifting. Was a junkyard tranny, hydro clutch, and not that it matters a 205 t-case. If you build the motor for torque, your current setup will be fine. Buddy had a K-5 with a 400 4-speed, 3.08s and 35" swampers, said it would pull away from traffic at a light....

[1976gmc20]

Originally Posted by kipps

That's very good mileage! I sure wouldn't be complaining.

With my old TBI 350, running around on the farm, I was getting 7 mpg. I'm hoping for 13-ish under the same conditions, once this LS swap is done.

I get about 12-15 mpg on my 89 K1500, 50 mile round trip to town and the rest puttering around on gravel roads and lots of low range chugging around in the woods. The 350 TBI pickup actually gets better mileage in those conditions than the six banger jeep, though it does a bit better on the highway, 20-22 mpg.

[kipps]

Originally Posted by 1976gmc20

I get about 12-15 mpg on my 89 K1500, 50 mile round trip to town and the rest puttering around on gravel roads and lots of low range chugging around in the woods. The 350 TBI pickup actually gets better mileage in those conditions than the six banger jeep, though it does a bit better on the highway, 20-22 mpg.

I'm not sure what all was wrong with mine. Possible plugged cat, possible wiped cam lobes, possibly low pump voltage, and goodness knows what else. If it was in proper trim, it would have done better. But I figured if I was going to put the effort into an engine, it might as well be a good one.

I'm sure the TBI is better than a carburetor. However I see it as just an intermediary step to a LS. If I'm going to mess around with a computer controlled engine anyway, it might as well be an LS.

This thread got off topic.

[SunSoaked]

Originally Posted by 1976gmc20

Just remember, folks drove all over the country in those trucks when they were brand new

And gas was 50 cents a gallon and the speed limit was 55. Economics.

[1976gmc20]

Originally Posted by SunSoaked

And gas was 50 cents a gallon and the speed limit was 55. Economics.

Actually, in 1970 the speed limit was 70 mph and gas was about 30 cents a gallon.

I remember when the price jumped suddenly up to almost 50 cents a gallon in 1974; it was not too long after I bought a brand new 1973 K-20. The speed limit change must have come about then.