Author Topic: SMason's 78 GMC K25 4x4 Build Thread  (Read 31440 times)

Offline BBM3

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #15 on: April 29, 2015, 06:18:05 PM »

The ends of your speedo cables should have square ends about an inch long and you want to make sure both square ends are fully seated. Light touch and a little wiggling to get the cable ends fully seated.

Your speedo ratio adapter looks like it is not tight to the transfer case. I can see oil leaking in your picture. I had the same problem.

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Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #16 on: May 04, 2015, 09:09:41 AM »
well I hooked up the new cable, the adapter was pretty darn tight but I got on it a tad bit more. the part that is loose is not at the nut its about a 1/4" up at a joint towards the cable.  All i can figure is it is just plumb worn out. 

I towed the rig to bay city (73 miles) and left it over there (closer to the beach back home).  I met with my cousin cause he said he had a driveshaft that might work for the front, so i looked at it and its too short by a long shot....so i have learned that apparently they made two versions a long and short....

he also had some goodies from a parts truck that i did not know he had bought, its an 80 with red interior so for the most part identicle he said he got what he wanted motor tranny and axles and whatever I wanted he would make a heck of a deal....I said shoot yea let me get a list together haha. 

Thinking about taking the dash(perfect condition) 205 transfercase, hood latch, front and side marker lenses, front headlight retainer rings, crossmember, heater switches, he said anything is fair game except for the cab itself but everything inside is game too
78 GMC K25 4x4 - Beach Toy
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46" Military XMLs

Offline English

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #17 on: May 05, 2015, 10:29:41 AM »
Try taking the adaptor out and screwing your speedo cable directly to the transfer case.
My speedo & odo didn't work, took the adaptor out of the equation and problem solved (yeah it's not accurate but I don't need it to be, just need the odo to work)

Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #18 on: May 05, 2015, 03:15:06 PM »
Oh wow well that makes since I suppose I am in the same boat I would rather have the odometer work than the speedo, Ima try it out
78 GMC K25 4x4 - Beach Toy
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Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #19 on: May 08, 2015, 10:24:41 AM »
Well parts and accessories will have to come to a stand still for awhile, only thing I am waiting on is to meet up with a guy for some front driveshafts, I will do what it takes to get them on, I will also put on the throttle return spring bracket I bought to move the springs to the front. 

I have to save up to get alot of work done on my daily driver about 3500 worth of stuff so it will be awhile till I have money to spend on the ole gmc sadly.  at least i got it to a point where it is drivable
78 GMC K25 4x4 - Beach Toy
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Zero Rates Upfront
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46" Military XMLs

Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #20 on: May 18, 2015, 02:38:33 PM »
I found a driveshaft (long style) out of a 85 the guy said so i put it up where it goes see if the length was going to be close enough and seems like it will work.  I took it to the driveshaft place here in town cause the ball and socket deal in the dbl cardone had failed. Getting all new u-joints, ball and socket rebuild kit and trimming a tad around the double joint for more angle gonna run me $150 thats with USA u-joints i forgot if he said neapco or spicer i dont remember greasable. I figured thats not too bad i guess and told him to do it.  He said he will have it done same day (today) which is great cause ill be needing the 4x4 for the beach this weekend. 

as for the speedo cable and adapter put the new cable on and tightened up a bit on the nut (what i could) and so far so good.  maybe the first cable wasnt seated properly. 
78 GMC K25 4x4 - Beach Toy
6in Suspension 2in Body
Zero Rates Upfront
ZZ4/TH400/NP203
46" Military XMLs

Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #21 on: May 26, 2015, 08:46:40 AM »












78 GMC K25 4x4 - Beach Toy
6in Suspension 2in Body
Zero Rates Upfront
ZZ4/TH400/NP203
46" Military XMLs

Offline FlatBlack77

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #22 on: May 26, 2015, 03:32:27 PM »
love the pics dude
"When you are a hammer, everything looks like a nail"
'77 C/10 - 350/350 mild street motor

Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #23 on: May 27, 2015, 09:16:00 AM »
Thanks man it felt good to be back out on the beach been too long for the black truck.  I got a video tearing up some mud but it was on my sisters phone and i cant seem to download them to my phone have to get them off of her phone or emailed to me.
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6in Suspension 2in Body
Zero Rates Upfront
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46" Military XMLs

Offline Car10s

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #24 on: May 27, 2015, 12:12:47 PM »
Wow! Great build!
Floor IT!!

Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #25 on: May 28, 2015, 02:02:05 PM »
Thank you,  There is way more than what i posted mainly cause I did not start this thread while doing it. there would have been alot more pics as well as more detailed notes of what all is new.  Basically in my mind some of the last things i need to make this truck be completed in my mind is a new cowl hood then i can get the thing painted. need new rear bumper would prefer a ranch hand type  bumper, new grill for the front, new dash or dash cover, umm little things but paint job is def high on the list.


I did manage to pick up a new to me toolbox for the truck.  Its the same one i have in my f350 and i like it alot.  found it on craigslist paid 60 bucks!!! i think its a heck of a deal!  here some pics of it up in the bed.  only bad part is you cant access it without climbing up in the bed haha! but should really be nice especially for the tools and fluids i want to carry just cant carry them without one and have them out of the way.




78 GMC K25 4x4 - Beach Toy
6in Suspension 2in Body
Zero Rates Upfront
ZZ4/TH400/NP203
46" Military XMLs

Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #26 on: June 01, 2015, 08:35:17 AM »
Got the front set up on for the throttle return springs and this is like night and day difference.  My pedal was stiff and hard and seemed like i was always fighting it.  Put the front set up on and the supplied "light" springs and it no longer has a stiff pedal and has quicker throttle response have noticed the gas gage goes down faster tho hahahahaha :o
78 GMC K25 4x4 - Beach Toy
6in Suspension 2in Body
Zero Rates Upfront
ZZ4/TH400/NP203
46" Military XMLs

Offline Don5

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #27 on: June 01, 2015, 10:45:02 AM »
Yeah there is always a trade off! BTW- The truck is looking pretty good.
It's been a LONG time since I have been called a newbie. Just sayin....

1979 GMC K15 355, SM 465, 205, 3.73 Dana 44 with a Spartan Locker, 12 bolt Eaton limited slip and 6 inch lift with 36 x 12.50 Super Swamper TSL's.

Offline Scott M

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #28 on: June 01, 2015, 11:36:15 AM »
Thanks man i appreciate it! you are right on that one
78 GMC K25 4x4 - Beach Toy
6in Suspension 2in Body
Zero Rates Upfront
ZZ4/TH400/NP203
46" Military XMLs

Offline Captkaos

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Re: SMason's 78 GMC K25 4x4 Build Thread
« Reply #29 on: August 17, 2015, 07:26:25 PM »
We need the highest resolution pic of this emailed to me


To potentially go in one of these slots if no one takes one...
http://forum.73-87chevytrucks.com/smforum/index.php?board=28.0