Best drivetrain combo for 4x4 crew cab

[BC3+3]

Greetings to all,

 This is my first post on this board, I'm hoping to get some opinions on which direction I should head in my upcoming build.  I've been playing in mopar land for the past while but want to get back into chevy as the aftermarket availability is just so much better.
My needs and lifestyle have dictated that my next truck have more than one row of seats and after test driving several newer crew cab offerings from the big 3 I decided that rather then drop $45 000+ on a newer truck that I will build myself a truck that can do everything and then some for less then half the coin.  

So long story short once I come back from my seasonal work in the North in July I will be searching the southwest for the cleanest rustfree 3+3 4x4 SRW I can find.  I plan on keeping this truck a loooong time and someday will probably repower it with a cummins, but for the immediate future I will be sticking with gas to keep things cost effective... and I am a sucker for V8 power.

So just to clarify, this WILL NOT be a tow rig.  It might tow the odd time, but generally not.  This truck will be mainly used as my camping/travel/dirtbike and snowmobile hauling vehicle and will spend alot of its time cruising around on logging roads and local highways here in BC.  I would like to be able to maximize my fuel economy at around 60mph (yes i know its a one ton brick and will suck fuel either way).  No such thing as an interstate in our neck of the woods. We drive relatively slow here as are roads are windy.  It will be getting a moderate lift (4-6") to accomodate 35" inch tires, nothing too wild.  

So, starting with transmissions, I really want a manual.  I prefer the extra level of control it offers.  The truck will spend most of its time on mountain roads here in British Columbia. and I like to be able to just stick the clutch in to disengage power to the rear wheels if things do get slippery.  In trying to keep this cost effective, I'm leaning towards finding a truck with a SM465 stock, as the granny low would actually be of considerable use to me.  Although expensive, I really like the idea of the gear vendors auxilary trans and I think it would make the SM465 a good application for this truck.  Also seems like the the least amount of fabrication required.  Open to opinions on this though....

Now the fun part...chances are the truck will come with a big block as this seems to be the norm.  Well I have always wanted to build a big block motor its hard to ignore fuel prices these days, especially when driving something like this.  Considering towing is not the primary purpose of the vehicle, could I get reasonable performance from a small block variant?  If I go this route I'm considering moderately built 383 as I think the available torque and the '7 speed' tranmission would match up quite nicely... in my mind anyways    
Whats the lifespan of a mild-moderately built 383?
Is 400ftlbs of torque realistic?
Any ideas what kind of mileage I might see at 60mph with a 383 and 465/gearvendors transmission?

Love to hear some feedback on all this.......  

[BC3+3]

I forgot to mention.... I'll be running a yet to be determined 35" inch AT or MT tire and likely keep the 4.10 gears, unless I can be convinced of otherwise.

EDIT:  I just ran the numbers on Randys RPM calculator. 

60mph with 35" tires  would have me turning 2362 RPM in 4th with SM465 and 1842 RPM in 4th over with the gear vendors.... actually works out better than I had planned.

[Captkaos]

I would use a NV4500 trans, but the 465/Gear Vendor would work...
Have you thought about the new LS motors.  They should yield good mileage along with power. (alot more than a stock one)

My 1991 CC SRW has the TBI350/4L80E and gets about 12mpg..  took a trip this weekend so I need to check it for highway..

[BC3+3]

Thanks for the reply, I have read a few posts on your crew cab project with great interest.

I was considering the NV4500, but after running the number$ it seemed to offer only a small savings over the cost of the gear vendors overdrive.  Another factor I am fighting is that where I live we don't have a ton of scrap yards to go fishing in and finding an NV4500 that won't require additional work to adapt it seems like a long shot.
Of course my current idea of using the 465 is assuming that the truck I purchase has one in it.  If this isn't the case then I may reconsider the NV4500.  But at the end of the day, I really like the idea of having the both the granny low and longevity of the 465 combined with the gear splitting capability of the OD unit.  Not to mention I've heard some mixed reviews of the NV4500, whereas the only knock against the old 465 is the lack of OD.

In terms of motors, I pondered going with FI, however I'd really rather stick with carb since going with the 383 would require getting a custom fuel/timing map and more $$$ and time.   I do plan on rewiring the truck anyways so i may yet change my mind to go FI, although it terms of fuel saving I've never really been that impressed by FI.  Sure it can achieve better mileage under ideal conditions, but most FI trucks I drive are only marginally better on fuel then a well tuned carb in my experience.  And tuning a modified motor with FI can be a troublesome task...

Nothing is set in stone at this point, but purely based on numbers I think the high torque output of a mild 383 matched up with a "7 speed" SM465 would be a pretty nice package and should be capable of rather impressive fuel mileage for a truck this size. 

[Captkaos]

I am talking about a complete motor (LS version)  You can probably get a whole drivetrain out of one for $3000 and it would have a manual and a t-case.

I know of several 5.3L powered 73-87 conversions that are getting 20mpg in the city.  No way are you going to do that with a carb and 383..
If you get a 6.0L our of a 3500 you start off with 300hp stock.

[Blue 82]

Get the HT383 crate motor
Made for trucks/towing
or duplicate one- forged crank/vortec heards/roller cam

While the gear venders OD is OK
have you seen the US gear dual range transmission
this will be better should you decided to swap to a cummins at a later time

http://www.usgear.com/dual_range.htm

[BC3+3]

20mpg is impressive for any truck... really in a crew cab 4x4 running 35's I'd be ecstatic with 15mpg hwy.  I ride my motorcycle (dualsported XR650R) for the most part so fuel mileage isn't the primary factor in this build.  I just don't want a single digit pig.  Another factor that was brought to my attention by a friend of mine today was that if I switched to a new FI motor I would not be able to get collector plates for the truck here in British Columbia.  Since this rig will only be a weekend warrior I would really like to be able to get collector plates as this would save me over 60% on insurace costs which is huge here as we have a messed up public insurance system which costs an arm and leg and has no alternatives.

Regardless, thank you for the ideas and I'll definitely be mulling this over while I'm up north working for the next few months.

Blue82, I had not seen US gear setup... I will definitely be looking into it more. The HT383 was the motor I have been eyeing, not sure yet if I'll buy it already built or get the local machine shop to assemble one.

[Cowboy_Customs]

Try this persepective out for a moment. You know your going to dump a ton of money into the drivetrain combo you want, yes? You mentioned the Cummins conversion, let me tickle your sences, there are tons of good cummins engines everywhere, u just gotta look around. Try this drivetrain combo on for size, 91.5-98.5 12 valve Cummins, GETRAG 5 speed, NP205.
The Getrag was equiped in the 89-93 dodge cummins trucks and it is an excelent transmission. They get a bad rap from the guys that didnt read the owners manual, and put GEAR oil in it. BIG NO NO! (10W-30 changed EVERY 20K miles, that thing gets hot!) plus if you fill it with 5 quarts, and not 3.5 it lasts even longer and runs a lil cooler, and shifts better
A junker 89-93 dodge cummins can be had for as little as 1000 bucks (ive even heard lower) The "first generation" Cummins 4x4's also came equiped with an NP205, with the front driveshaft on the correct side for a chevy.
Oh yeah hows 20+ MPG sound? With a final gear ratio of 3.55, anything over that is too much. So 4.10s and 35's yield very close to that

In the end it is cheaper to just get the truck and do a Cummins conversion, with the Getrag, and 205. Plus a Chevy NP205 i believe is a direct bolt on to the getrag. (I can confirm that but gotta get ahold of a friend of mine)

Im kind of in the same thinking as you, I want a big Nutz BIg block, BUT after owning a Cummins, If it dont blow black, take it back! I am going to eventually convert but how soon I dunno.