1984 GMC 1/2 ton. Want to modify please help!

Discussion in 'Suspension, Steering & Brakes' started by Rohrs84GMC, May 10, 2017.

  1. Rohrs84GMC

    Rohrs84GMC Full Access Member

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    Truck Year:
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    Truck Model:
    k1500
    Engine Size:
    350
    Hi guys, sorry I am still super new here. I finally have the time and some money to stop neglecting my truck! There are so many options out there I'm a bit stumped on which direction to go.

    A bit of background:
    Mostly stock 84 gmc 1/2 ton
    350 v8
    TH-350 trans
    10 bolt rear end
    Quadrajet carb
    Air conditioner
    Stock 3:08 gears

    What I think I want:
    I want to keep it the height it is
    I really want to drastically improve the ride comfort
    - maybe seat swap?
    - suspension upgrade. something truly awesome. But reasonable as far as required modifications
    I would like a bit more get up and go
    I want to keep be able to drive it daily/long distances without feeling like I worked out!

    What I was planning so far
    Jeep steering shaft swap
    Rebuild Carburetor
    Pull the motor, change all seals, freeze plugs, adjust lifters, paint everything I can while the motor is out, replace vacuum lines, belts, and water pump

    Other than that I would love suggestions on what else you guys consider I attack to reach my goals.

    I promise I will make a very strong technical write up for all work I perform.
     
  2. 1987 GMC Jimmy

    1987 GMC Jimmy Full Access Member

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    It sounds like a nice truck. I'm assuming it's a Southwestern truck so it'll be a clean starting point. I like your idea about the suspension stance so I'll leave you to that. I'm not the most knowledgeable about suspension, but I can tell you that a good set of shocks will go a long way. I would also make sure that your ball joints are in good shape. The world is your oyster on the seat swap. You can pretty much do anything within reason. I like the Blazer/Jimmy/some Suburban/some Crew Cab bucket seat and console conversion. It's a pretty traditional way to go, and the seats are super comfy. As far as upgrading the suspension, like I mentioned about a good set of shocks and the steering components/ball joints. I know Moog makes a high end kit for our trucks. As far as more get up and go, that ring and pinion set you have is a dog. You don't want to get crazy with the gears since you want a daily/long haul type truck so I'd suggest 3.42's.

    Again, great call on rebuilding the Q-Jet. You can definitely do it yourself, but there are good mail order people doing it, too, and they can press in a bushing for the throttle shaft because the shaft wears into the body of the carb on higher mileage units. I would suggest either Quadrajet Power or Mountain Man Carburetor & Fuel Injection. If nothing else, both of those guys can suggest a rebuild kit that'll get the job done. My third good call for you is the XJ steering shaft. It's the best cheap mod out there, and it really makes a difference. Since you're pulling the motor, I would suggest working to give it a little more oomph than an 80's 350 had. This would include a set of long tube headers, a cam swap, an aftermarket intake, and maybe do some research on what head casting you have to see if you want to keep them as are, port and polish, or go to Vortec or aftermarket heads. Check out the Comp 12-300-4. That right there will really wake up the engine, and it won't do anything to your economy except maybe improve it to where it compensates some for the gear swap. I don't know how all out you want to go here, but an '87 or newer 700R4 built nice with a shift kit would be a nice complement to your gear swap because you'll be cruising at higher RPMs with shorter gears and a TH350. I don't know what your emissions constraints are, but if you're still running the factory cat, I'd lose it. Either delete it entirely, punch it out, or replace it with a high flow unit. I will disclaim that removing it altogether will not conform to federal emissions regulations, but that's how I run both of mine. Punching it will make it look like it does, and a high flow cat will conform to federal regs. I would inspect the timing chain and gears just for good measure and do a new timing set if there's slop. I don't know if you can budget in all those suggestions, but that's most of what I know to do and all I can think of at the moment.
     
    Last edited: May 11, 2017
  3. theblindchicken

    theblindchicken Full Access Member

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    For get up and go, you can either swap gears, which will give you quicker acceleration, but drops your top speed and will increase your rpms at any given speed. May not do a whole lot to your fuel economy.

    Engine wise, rebuilding the carb and a fine tuning again will make her a bit peppier too.


    For the suspension, I would recommend checking the spring and shackle bushings to see if they need to be replaced yet. If not, ensure they get a nice healthy coating of grease. Do that front and rear.

    Check your shocks to see if they're too stiff, may wanna get a newer pair with lighter dampening if they're too stiff for ya.
     
  4. smoothandlow84

    smoothandlow84 Full Access Member

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    1500 r10 pavement scraper
    Engine Size:
    350 TBI
    Replace the rubber bushing with polyurethane. Shocks, rebuild the carb and do a full tuneup including plugs, wires, dizzy and plugs.


    welcome to the site!
     
  5. MikeB

    MikeB Full Access Member

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    Those two items above go hand in hand, but remember it's a pickup truck built when people didn't buy them as smooth, quiet, luxurious daily drivers!

    Aftermarket suspension kits (and probably even complete frames) are available that use coil-overs or air bags, but they are very expensive.

    What kind of tires does the truck have? A load range D truck tire can be harsh and noisy. Use something like Cooper Cobras or BFG Radial T/As for a smoother ride.

    Worn shocks will cause the truck to bounce and wallow more. If the bushings are worn out, they may even be noisy.

    Check the sticker inside the glovebox door to see if your truck has the optional HD suspension with stiffer springs. If it does, consider using standard duty C10 springs.

    As mentioned elsewhere, it's always a good idea to replace all the suspension bushings. If yours are original they will be cracked, and worse case may even cause metal on metal contact.

    And while the control arms are off the truck, you might as well replace the ball joints, unless you know they are reasonably new.

    Use name brand suspension and steering parts like Moog! I can't overemphasis this.

    Visually inspect the cab to frame mount bushings for cracks or deterioration.

    Yes, definitely keep us updated.
     
    Last edited: May 18, 2017
  6. Camar068

    Camar068 Supporting Member Supporting Member

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    10 yrs Air Force
    Plenty of options mentioned above. If it were me and I pulled the engine, I'd have to upgrade something, if not rebuild it. Maybe keep an eye out for a 350 or 400 and rebuild it the way you want it, and just give your current engine a good tune up? Or find a 305/350 that you know is running and swap it out and rebuild the one that's in there now.

    Just another option to add to the list.
     
  7. Honky Kong jr

    Honky Kong jr Full Access Member

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    LSA........!milage and peppy too....
     
  8. 74 Shortbed

    74 Shortbed Full Access Member

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    Better yet put a 540 in, fock the mileage. :D
     
  9. Honky Kong jr

    Honky Kong jr Full Access Member

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    ZZ572 or LSX454.........and body swap onto a Caprice 9C1
     
  10. 74 Shortbed

    74 Shortbed Full Access Member

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    Can build a 540 with more power for less money than what they want for a 572. :D
     
  11. Honky Kong jr

    Honky Kong jr Full Access Member

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    Yes I know I was being rediculous ok geez:whymewhyme: I have been thinking of a body swap that right up my alley of hackery. Ford guys are doing it with F100s on Crown Vic frames. Why can't us sane people do it with C10s?
     
  12. 74 Shortbed

    74 Shortbed Full Access Member

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    No reason why not, just keep it RWD..
     
  13. 1987 GMC Jimmy

    1987 GMC Jimmy Full Access Member

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    I hope the OP's come back to this. This thread's a treasure trove of suggestions.
     
  14. MikeB

    MikeB Full Access Member

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    Could be a drive-by thread-starter.

    Treasure trove of suggestions? As in put a 540 in it? :)
     
  15. 1987 GMC Jimmy

    1987 GMC Jimmy Full Access Member

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    Yeah, you're right. And ehh, minus the 540/572. I think the C10 on a '91-'96 9C1 Caprice frame is an interesting idea, but someone would need to blaze that trail first. Regardless of practicality, I think talk of any frame swap is an interesting topic. Even then, a lot of good stuff's been discussed.
     

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