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1970 GMC Jimmy - Grandfathers Unfinished Business

That's a rad rig!

Was it up in Tahoe? I see the West Shore license plate frame.
 
Looking at those pics I'd check the upper radiator hoses as they look swollen to me. It's also good to check that pipe that connects the two hoses while you have it off, but hold on to it, as it's original and desired by collectors and a bit harder to replace. Also, I'd put in a new rubber PCV grommet (driver side valve cover) just to keep the engine bay clean as it looks pretty dry rotted.
 
ekajkrats said:
Looking at those pics I'd check the upper radiator hoses as they look swollen to me. It's also good to check that pipe that connects the two hoses while you have it off, but hold on to it, as it's original and desired by collectors and a bit harder to replace. Also, I'd put in a new rubber PCV grommet (driver side valve cover) just to keep the engine bay clean as it looks pretty dry rotted.
Click to expand...
Thanks. I ordered the grommet.
 
New battery, replaced fluids (diffs, transmission, oil, transfer case, power steering, brakes, etc.) and got the truck running smoothly this weekend. I tried to upload a video but was too big to post, will try again later. It sounds awesome, surprisingly smooth.

Tires have a date code of 1986...Dunlop Radial Rovers in 33x12.5x16.5. Came across an unexpected issue (I thought ordering tires would be an easy step)...it seems that 16.5 is essentially obsolete now? That true? Anyone know of a solution? Or do I need to get new wheels...?
 
Those 1986 tires are probably either petrified or cracking by now,and likely are flat spotted permanently if the truck sat a long time..
You may get away with using them "around town",but I'd be leery of driving on them at highway speeds..they might chuck the tread without much warning..

16.5's are rather obsolete ,but some can still be had in certain brands,and the military Wranglers are still around,but it would probably be best to ditch those rims and get 17" ones if there are any stock ones off newer trucks with the correct backspacing..

16.5's suck as far as the beads,most don't have a safety bead and can come off at the rim bead easier when you air them down low..
15" tires are starting to get harder to find now too,17's are more popular and give you a wider selection to choose from..
 
diesel4me said:
Those 1986 tires are probably either petrified or cracking by now,and likely are flat spotted permanently if the truck sat a long time..
You may get away with using them "around town",but I'd be leery of driving on them at highway speeds..they might chuck the tread without much warning..

16.5's are rather obsolete ,but some can still be had in certain brands,and the military Wranglers are still around,but it would probably be best to ditch those rims and get 17" ones if there are any stock ones off newer trucks with the correct backspacing..

16.5's suck as far as the beads,most don't have a safety bead and can come off at the rim bead easier when you air them down low..
15" tires are starting to get harder to find now too,17's are more popular and give you a wider selection to choose from..
Click to expand...

Thanks. Definitely inimizing time on the road until I get some safer rubber.

I poked around on here, online, at the tire fitment guide but tire/wheel/backspacing still makes my head spin. You guys know of a thread here with different lift / tire / wheel combinations?
Hoping to stick with 33". (currently 33X12.5X16.5)
Has a ~2" lift and will keep it there.
Trying to figure out wheel spec needs. Something like 15x8 with 4" backspacing?
 
Also, if it were me, I would measure what you have for your existing backspace and order that in a 15” or 16” rim with some new wheels of your liking that are 33’s. You know that combo will work. Wheels that fit 16.5” rims are becoming more and more scarce.
 
I've been Craigslist / Ebay / Forum searching for used wheels but not having great success. Seems like old school Rally's should be everywhere!

Current Setup: The ones I'm replacing.
33x12.5x16.5 (the 16.5 is the killer). 4.5" backspacing. Don't know offset.

Looking at these wheels:
https://www.summitracing.com/parts/wvi-31-580604/overview/
These aren't that expensive and seems they'll do the job. I just hate buying something so heavy online because returning isn't really an option.
I also I hate that first customer review :/ (Is there some other known vendor that I should be looking at for Rallys?)
Major difference vs current setup is the new wheels have 4" backspace (instead of 4.5")
The center bore is 4.25" and current wheels are 3.5". My understanding is that I can get hubcentric rings to fill the gap.
I think I'll pair with 33x12.5x15 BFG KO2s
 
Dan_P said:
I've been Craigslist / Ebay / Forum searching for used wheels but not having great success. Seems like old school Rally's should be everywhere!

Current Setup: The ones I'm replacing.
33x12.5x16.5 (the 16.5 is the killer). 4.5" backspacing. Don't know offset.

Looking at these wheels:
https://www.summitracing.com/parts/wvi-31-580604/overview/
These aren't that expensive and seems they'll do the job. I just hate buying something so heavy online because returning isn't really an option.
I also I hate that first customer review :/ (Is there some other known vendor that I should be looking at for Rallys?)
Major difference vs current setup is the new wheels have 4" backspace (instead of 4.5")
The center bore is 4.25" and current wheels are 3.5". My understanding is that I can get hubcentric rings to fill the gap.
I think I'll pair with 33x12.5x15 BFG KO2s
Click to expand...
If for some reason you do have to return them, it gives you a reason to drive up to Sparks and return them. :D
 
I agree that truck is a beauty !...

I had a set of 6 lug 15.5" rims on my '72 K5,I found them for sale chained to a telephone pole with "Armstrong"12:00 x 16.5 lug tread tires that were bias plys--they came off a '71 GMC K10,they were a rare option supposedly..took me months to find a 5th one,for a spare tire!..

Those Armstrong tires were so hard riding,all petrified, I had to buy 4 new tires ,I found a place that was closing out all their bias plys ,I got 4 Cooper 8:75/16.5 load range E tires for $100 mounted and balanced...this was back in the mid 80's when radials were taking over..

Nylon belted though ,felt square after sitting overnight for the first 5+ miles,but they wore like iron and I never had one get a puncture--the tires & rims went on two other trucks after I moved back to 15" tires and bought radials for some steel rally wheels for the K5..truck rode so much smoother with BF Goodrich TA's that were 30 x 10.50 15's and 4 ply passenger rated it was like going from a one ton dump truck ride to a cushy smooth non-jarring ride..
 
Looking for some Carb input of how to proceed.

Carburetor needs a tune. Trying to figure out the best option.
- Rebuild: Hourly rates are pretty expensive in Bay Area. I haven't gotten it quoted but I suspect a Carb Rebuild/Tune is a couple hundred bucks?
- New: It looks like new Holley Carb is $350-$400.
- EFI: Lastly option...but maybe bite the bullet since I plan to keep this car forever? Obviously much much more.

My primary considerations are Rebuild vs New. But in the back of my mind EFI is there.

Let me know your guys thoughts. Thanks!
 
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