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1987 V20 Suburban 350TBI/SM465

I should have posted this in the Build section...I don't see how to move it myself...is that a thing mods can do?

why yes, yes we can. it has been moved
 
Day 1: Found a small leak coming from the coolant reservoir, knock and O2 sensor codes (13 and 43), its hot and loud as hell on the highway, and missing the 2nd row shoulder belts.

Going to start with tinting the windows with a ceramic film and Kilmatting the shit out of the bare roof, cargo area, and any exposed metal. I'll have to look more in to pulling the seats and rubber flooring out to insulate all of that. That front bench seat isn't the most comfortable with my long legs so I'm thinking I'll pull the floor up when I replace those. I've pulled Suburban carpet before but never put in insulation and tried to reinstall flooring over it. The OEM insulation and rubber flooring goes all the way back to the barn doors so lots of area to cover.

Tinting will go on everything except the windshield. Its got several large chips and needs to be replaced first.

O2 sensor looks broken in half at the nut, wire is just dangling there. Knock sensor looks intact but I'll replace both today.
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Coolant reservoir leak seems to be coming from the underneath side of the tank, not from the hoses. I'll get that ordered this week.
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Also looking at two of my tires, I'm not sure I'll pass inspection to get it registered. Guess I'll be doing the lift and tires pretty quick here. Oh no...so upset. The front spring look so tired anyway.

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Nitto trail grapplers, they measure an honest 37”
Lift is 5” ish
Lots of fender work, but the 73-80 fenders are shaped a little different
 
Why lift it? It's almost perfect as is?

An '88 would have an NP208. Switching to an NP205 would require a lot of changes, and would be a down grade.

Martin
 
For some reason I thought the 205 was better... vs gears I guess. But several people have now mentioned the same as you.

I want some more ground clearance and bigger tires. I'm leaning towards 37s but I know I probably don't need that large.
 
I think you would be happy with a zero rate, and some 33" tires. Is the SPID still in the glove box?

Lift sound fun/cool, until after you do it. Unless you need the clearance, it is more of a nuisance/complication. I see you already have the three pack of front springs, I would suggest a zero rate, and a 1" body lift. It will ride like stock, and give you a little tire clearance. You're fenders are far too nice to cut, otherwise you could fit 37" tires with just that amount of lift.

As for the transfer case, your NP208 has a 2.61:1 Low range. An NP205 has 1.96:1 Low range. I doubt you plan to bounce the transfer case off of rocks?

Martin
 
I'll check the glove box later after I'm out of meetings.

I had a K20 Suburban about 15 years ago with 4" and a zero rate and 40s with some trimming. It wasn't a daily driver or anything but I didn't mind the lift. Can you elaborate on the nuisance/complication you're talking about? I want to weigh the pros/cons of these different ideas. I do plan on hauling the family around so I don't want it to be too big where its a pain to climb in.

The stock ride is bouncy and rough (no surprise there) but I was hoping some new quality springs and shocks might make it a little smoother. I do plan on adding some weight as well in the future.

At higher road speeds, the lack of overdrive is a bit harsh and I was also considering that 37s with the SM465 and 410s (I need to confirm that) might help with that but I guess adding height and larger tires could make the ride worse, even if it helps my 4th gear speeds/rpms

Transfer case...no plans for serious rocks. I'd like to be able to do trails but no real rock crawling in my plans.
 
Yeah, I have an '85 K20 with an SM465 and 36" tires with 3.73 gears. It goes down the highway fine, but is a little low on low end grunt.

Martin
 
What size tires are on it now?
I had a 77 with sm465 33s" 4.10s
I used a tuff county ez ride 2.5" lift front and rear springs tuff county shocks. Only a slight rub front edge of fender. 8" wheel forget offset.
 
Current tires no wear are 31.7" in diameter.
If you get true 33" you will drop @120 rpm in high gear. True 35" will get a @220 rpm drop in high gear. So @2300 at 70 with 35's.
2nd gear starts might still be possible. That's 12.2 to 1.
 
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37s on a 3.42 is a task. Takes some grunt to pull that
 
Bent77 said:
37s on a 3.42 is a task. Takes some grunt to pull that
Click to expand...
Yeah that’s what I’m thinking. So of I just stick to 33s, of there any reason to replace the springs with new stock height springs? Those front ones look so droopy.
 
Front ones are reversed arch. 3 spring front pack would be good

If they are new stock height springs, you may have some rubbing with 33s. Won’t notice much power loss. With 37s the engine wouldn’t like you much. I’m running 420 hp with 4.10s and still need 3rd and a half gear and OD
 
Bent77 said:
Front ones are reversed arch. 3 spring front pack would be good

If they are new stock height springs, you may have some rubbing with 33s. Won’t notice much power loss. With 37s the engine wouldn’t like you much. I’m running 420 hp with 4.10s and still need 3rd and a half gear and OD
Click to expand...
Makes sense. So then maybe new stock height springs and a zero rate and 33s then.
 
fordmas said:
I'll check the glove box later after I'm out of meetings.

I had a K20 Suburban about 15 years ago with 4" and a zero rate and 40s with some trimming. It wasn't a daily driver or anything but I didn't mind the lift. Can you elaborate on the nuisance/complication you're talking about? I want to weigh the pros/cons of these different ideas. I do plan on hauling the family around so I don't want it to be too big where its a pain to climb in.

The stock ride is bouncy and rough (no surprise there) but I was hoping some new quality springs and shocks might make it a little smoother. I do plan on adding some weight as well in the future.

At higher road speeds, the lack of overdrive is a bit harsh and I was also considering that 37s with the SM465 and 410s (I need to confirm that) might help with that but I guess adding height and larger tires could make the ride worse, even if it helps my 4th gear speeds/rpms

Transfer case...no plans for serious rocks. I'd like to be able to do trails but no real rock crawling in my plans.
Click to expand...
I have an '89 V2500 burb, TBI 350, SM465, stock height, 245 tires. Also have a '91 V3500 crew cab, TBI 350, 4" lift, 37" tires. Also have a '90 K5 (8 lug), TBI 350, 4" lift, SM465, 37" tires. All 3 have 4.10 gears. The point here is they drive very different. The 37" tires drop the rpm at highway speed but also suck up all the power. 7000ft elevation and up here so no power anyway. The crew cab towing 2 snowmobiles leaves me floored in the mountains and I have no power to spare, barely keeping up with 70 mph speed limit. Add a headwind and its 55mph. The suburban on stock'ish tires will pull a 4 place snowmobile trailer loaded no problem at 70mph. The K5 feels like it has more power than the crew cab but its only because of the weight difference, it's slower than the suburban going to the mountain. I will leave my burb alone, there is a 454 in the K5 now waiting for an EFI kit on backorder and the V3500 has an 8.1L waiting for it. I have the luxury (stupidity?) of having 3 squares so I get to set them up differently. My crew got the lift because I love how it looks, now I need more power or gearing. The K5 got lifted for wheeling but it also needed more power and gearing. The suburban is just nice how it is and is very useful. Be honest with what you are planning for your suburban and how much time and money you want to spend before you start down the modification path. Or just order a 502 and some 40's.
 
Lots of great info from y’all. I think I’m going to refresh the front with new stock height springs, zero rate, and and some 33s for now. Found some 3 and 4 leaf packs. Then focus on the interior and make it comfy and start using it. I’ll figure out what I like and if I want to upgrade things that way.
 
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