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71 GMC 4x4 4BT

9K views 27 replies 9 participants last post by  Dale_1972 
#1 ·
Hi, I am just now starting my build thread. This is my first time ever posting. So I'm new to this, but I've been reading everyones post on here for the past few years while I've been working on this truck. My goal for this truck is to make it my daily driver. Above average horse power, possibly up to 150 hp. I also want it to be as fuel efficient as possible for the type of truck it is. I bought this truck a few years ago in Ft. Myers, FL and brought it back to Indiana for restoration and diesel power train. I've got a lot of pictures for this build from the beginning to the end. I'll post some as I get the opportunity. Right now I'm in the final stages of completion. Almost ready for the tuning stage. Here's a pic of where it all started in Ft. Myers. And a pic of where it is now, almost at completion.
I'll back up and share some of the build process and lessons learned through this journey.
 

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#2 ·
Super sweet, can't wait!
 
#19 ·
im just south of columbus in scipio, would love to come see your truck sometime. im wanting to do another swap into an old chevy like this next.
Your welcome to see it anytime . Pm me and I'll send you my # so if or when your in the area you can stop by. I also have a 1969 Dodge 4x4 waiting for transplant . I have a 92 innercooled engine and a zf to put in it, I'm considering a rto 6610 though. Waiting till I get all the little bugs worked out of this GMC first . I have a nice video of the gauge with it running on the interstate if I can get it posted.
 
#4 ·
Sounds good. !40-150 HP is plenty for a very useful, driveable, enjoyable rig while still getting excelent mileage, as long as overall gearing is correct.
 
#6 · (Edited)
Here's a picture with the engine in place. I was working on setting up the HY35 with a 24 valve cut down manifold. I did get it to fit where I like it, however, I did not use this setup. I used a HX30. Which fit almost in the same identical place including the exhaust and all. Here is a pic of the motor mounts. Wasn't sure at the time on how to set these up, I haven't really seen any good pics on how to do this. They do work fine. I used first gen. motor mounts in between the angles. I will be replacing these with the hydraulic motor mounts. Since I've driven it just a little bit I can feel a little bit of vibration at cruising speeds between 55 and 60. Probably will consider in the future the fluid damper balancer. Also, to get the oil pan clearance without modification I put a 4 inch lift kit on the truck. It has a NV4500 transmission which mounted to the original transmission mount in the same location. I used a Chrysler mount for the transmission. The NP205 transfer case shifter worked out almost in the same place as the original turbo 350/NP205. I am running the original gears in this truck which is 3.08 and 33 inch tires.
Today I took it out for a quick trip. It cruises 60 at 2,000 RPM's in 4'th gear. So the 5'th gear with this setup will be a true overdrive. Probably won't use it unless I'm running 63/64 or over.
The driver side motor mount is not as close as it looks in the picture. I'm open to suggestions if anyone has any pics of how this setup would work better with the hydraulic mounts.
More to come soon!
 

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#8 ·
Do u like the power with those gears? I'm doing the same 3.08 with 33's and I'm worried I might be too tall.
 
#9 ·
I have only drove it about 200 miles so far. I think it's doing really well 1st does up to 10 mph, 2nd 10 to 20,3rd 20 to 40,4th 40 to 62 , 5th 62+.
If I can get it posted, ill post a little video of my gauges on interstate .
This engine is a factory nonintercooled , stock injectors, pump was tune 10%above spec ,hx30 turbo , no fuel pin or spring yet. It does have a intercooler though, from a first gen dodge.
 
#10 ·
Sweet
 
#11 ·
So how was your pan to pumpkin fit? I have about 3" to my bump stops, had to change out the quick drain plug and grind my pumpkin a little. Nothing a lift kit could of fixed but I liked the stance. great truck! Jeff
 
#18 ·
I've got over 3000 mile on it now . It runs out really nice with the current gearing with plenty of power. I still havnt done any extra tweaking on the pump yet, although it is set 10% above spec. . I havnt nailed down the fuel mileage yet I think it's doing around 25 mpg.
I need to install cross over steering, does anyone have any suggestions with good results ? I have to much play and bump steering .
 
#20 ·
I started the tuning process. Added a m&h 3 fuel pin with no other changes , not much different , just a big cloud of smoke when I shift gears. After reviewing some of the other recent threads about the hx30 I though I would do some more investigating on mine. I have 3 different ones ( 2 6cm , 1 12cm ) . The 12 cm has a bigger compressor also . So I want change it and put it on the 6cm . Is there any reason why I shouldn't do this?
 
#21 ·
Hmm... not sure why it wouldn't work but perhaps dougal will chime in here... I'd say the wheel and housing will bolt up.

Truck looks good man... You should probably make the trip to Indy for the 4 wheel jamboree in September.. we go up every year and I'd love to check out the truck.

As far as tuning goes.. what are your power goals? Do you have a pyrometer as of yet? If not.. no more tuning... lol. If you do, then I would adjust the star wheel a bit to help with low end smoke or go back to the stock pin and rotate it to the deepest cut... then adjust the power screw in a bit. If you really want to take advantage of the extra fuel with that pin... compounds! :)

-Chris
 
#23 ·
Want to get to around 30 on boost( make it better daily driver). I do have a pyrometer ( up 1100 temp) and boost gauge ( 20max) . I was hopeing the compressor on the 12cm split scroll would really help the 6 cm. Also is there a ( measurement ) or a way to gauge the waste gate to help achieve the 30 psi boost . Also my pump is only 10% above spec.
 
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