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Some questions about a 83 K5 Blazer.

5K views 10 replies 5 participants last post by  75gmck25 
#1 ·
I've been thinking about buying/trading for a K5 blazer and I don't really know a whole lot about 4x4s. What would be some of the stuff I'd really need to look for on this thing to make sure it's got a good strong frame/suspension and stuff.
The engine was completely rebuilt/mechined less then 400 miles ago, it's just a 350 with a upgrade comp cam and it's been bored out(I don't know much more about it).
The tranny is a 350 turbo that was completely rebuilt aswell as upgraded with stuff I've no clue wth he was saying..lol...He said it'd hold up to around 850hp (The guy who told me this stuff is very trust worthy so it's no fib, he knows alot about the engine/tranny in the k5 but little about the rest).

 
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#2 ·
If its a TH350 then its probably not the original transmission. By '83 they had started using the 700R4 overdrive transmission. This means you also need to also look at the transfer case to see what you have.

The most likely model is the New Process NP208, which is a medium duty chain driven case. The best would be the gear driven NP205, but this would be uncommon even as a swap. They were only used on older trucks, and often only with a 4 speed manual. The chain driven full time NP203 is also a possibility, but it was also only stock on older trucks. You may want to look at this link to see the differences Tucson Off-Road Forum • View topic - Transfercase Identification----CHEVY TECH .

Based on the lift I would also try driving it over some rough bumps to see how bad the bump steer is. They should have installed a dropped pitman arm (like this one Offroad Design - Steering Correction) to keep the steering lined up with the axle, but some folks skip that step. It can make it very hard to keep on the road when you hit bumps.

Another place to check is where the steering box is bolted to the frame. With big tires this is a high stress area and the frame may begin to crack. You can weld on or bolt in a reinforcement for the frame (like this one ORD Chevy GM Steering Box Brace and Bolt-in Frame Repair).

These trucks are relatively cheap to keep up because they are built like a tank, and most of the drivetrain parts are identical to what was used on cars. You can almost always find parts in the junkyard, or at a reasonable price from an auto parts store. Their weak point is body rust, especially the lower sections of the cab and fenders. If you run it hard you are also going to break things, but that's also the case with a newer truck.

Bruce
 
#9 ·
The best would be the gear driven NP205, but this would be uncommon even as a swap. They were only used on older trucks, and often only with a 4 speed manual.
Sorry, but that is not correct. The NP205 was used in the 1-ton trucks through the 1991 model year (in the old body style trucks). They were used with ALL transmissions, including the 4L80E in the 1991 model year only (now THAT'S a rare combination, since it was only used in the crewcabs and possibly 3/4 ton Suburbans).
 
#3 · (Edited)
Oh yes I forgot the case was upgraded to a gear driven case.

The transmission was built for a hotrod car my boss made a long while back... sold it to his son and he ended up getting the transmission completely rebuilt just before blowing the cars engine up.. it end up in the k5 and he sold that to one of my co workers who blew the engine up. My boss told him that the engine was upgraded because he'd just bought it from a guy who said it was upgraded aswell... turns out it was a lie when they got into the engine after it exploded so my boss bought him a new engine got everything mechined bored and a valve job of some kind... I'll get more details on it soon but the truck did drive decent side from the steering was loose(I'll check if it had the steering correction thing) but I plan to buy new steering box to get it driving somewhat better I guess.
 
#4 ·
Blazers make a nice beater. They are too wide, too heavy and too made-for-the-street to keep up with the Jeeps, but are a wonderful way to get into four-wheeling. Oh, and your milage will always suck bad. On the plus side, they are built like a tank...the frame under that thing is 3x the strength of a Wagoneer. If the steering box is ever breaking away as noted above, that's a weak point but an aftermarket bracket fixes it.

The steering drag link is designed in line with the leaf spring...it takes a lot of lift before you get problems there so you're probably OK. If the steering isn't working right, it's likely something else. Blazers are nice handling trucks even with the short wheelbase, but all the front end parts incl. ball joints need to be in good condition. As for the steering box, those will normally go a long long ways and not need rebuilding so don't automatically be changing it. Be sure you know what the problem is before throwing money at it.

Umm, on second thought, that lift does look a little excessive...maybe you're on your own there...:D

The truck in the photo does not look like an '83...it has the old-style pre-80 front fenders. If it has a TH350, that would be the right trans for the era. Be happy, 'cause the early 700R4s are NOT reliable and you don't want one. Better to be without the overdrive, and have it work, "850hp" claims aside. Also if it's an earlier model it will have something like 3.73 gears with a Dana 44 front end...all good, never mind the mpg. '80s trucks used 10-bolt fronts with 2.73 (!) gears, way too tall for a 4x4 and didn't help the milage anyway. But...don't go jumping off of things with that Dana, it'll bend in the middle, one area it gives to the 10-bolt. You can truss it underneath with an aftermarket kit.

If the 208 transfer case has been replaced with a gear-driven one (205), that's interesting and good, but unless you're some serious stuff, the 208 is enough.

Old Blazers are their whole own thing. If you get it for a good price (don't go paying too much now) it'll be a blast.
 
#10 ·
so.. I did buy the blazer and it is a 80 not 83... so yeah whoever said it looked older was right. :) Fun ride, will be better once I replace the steering box though. No cracks on the frame or crack fixes from what I can tell and everything seems to be running good for now.
 
#11 ·
If you replace all the common wear items it will take a lot of the "wander" out of the steering.

You can adjust the steering box to take out a little of the play, but don't get carried away. If you get it too tight it will start to bind. There is an adjusting screw with a lock nut on it, right on top of the steering box.

I would also replace the drag link (or inner tie rod), and possibly both outer tie rods. However, the side with the longer outer tie rod is quite expensive because you can't just replace the ends. There should also be a steering stabilizer (looks like a shock) that runs from left to right and connects to the steering.

Bruce
 
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