sorry for the non-third gen topic, but i want to get a K5 and I know I can get some good help here. Basically my main worry is rust. I want to know if there's any common spots where rust starts on these trucks so i know where to check. also, does anyone know of a good website for blazers, kinda like this one? thanks for the help

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350, Comp 262, Edelbrock Performer intake 600 cfm carb and exhaust, headers
-JVC, Eclipse, Pioneer, MTX, Phoenix Gold, Planet Audio

 

I believe I can answer your questions.

I have a 76 GMC Jimmy 4x4 400sbc. Rust Happens. Most common places are: Bottom of doors, front fenders at the back lower edge where leaves & debris fall and catch moisture, Windshield A'pillar, when windshield seals get old and water runs down into channel under seal and glass and rusts out the lower corners, the rain rail seams over the doors, and the area right at the cabroof/body seam/seal to fiberglass top (few inches from door handle).

Certain year models have worse problems. When the half metal cab roofs came about in late 75, that created a whole bunch of spots for water to get trapped. The changes in the paint prep process also caused problems because they no longer pre-dipped the panels prior to painting. These problems carried through till the mid 80's.

As I've looked for a replacement through the years, I keep leaning toward ~89-92 year models: Better body panel paint prep, revised drainage and better assembly, not to mention better interiors/options.

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KevinP92Z
92 Z28 383 SLP cam,SLP headers,SLP 2ontheLeft,Trick Flow TW heads & pistons,Edelbrock base,Accel SuperRam,52mmTB,Scat Crank & forged ConnRods,MSD 6AL,SLP convertor,Baer 13/12" Track,Moser axles,Hotchkis,Genuine GM 3.42s,SLP HD Torsen,17x9" chrome SS rims
96T/A w/SLP Ram Air,SLP 2ontheLeft, Bilsteins, Baer, Hotchkis, Genuine GM, Torsen
76 4X4 Blazer 400TPI project

 

Another truly weak spot was the drivers floorboard/rocker panels. (I had a 79 for a LONG time, loved that truck....) They seem to accumulate water, and away they go. (especially in states where salt is used on the roads in winter....)

Great trucks though. In the late 80's, early 90's, the metal treatment got significantly better, they started using two-sided galvanized metal, alot of the rust problems were reduced that way. (but NOT eliminated)

What year are you looking at?

 

im lookin at late 80's, preferrably something w/ tbi (i dont think those had tune port right). my main worry is rust, pretty much anything else is relatively easily dealt with. I had a 79 that someone gave me for free...it was rusted to hell, especially the floor boards. the first time i took it off road i got covered in ****, but it was fun...also the frame was cracked in the fron, between the 2 leaf mount on the pass side...definately made for a much bouncier ride. but i liked the truck for what it was, and i could imagine how i would like one in half decent shape. i actually sold the free truck for $200 so it wasnt such a bad deal...anyway, thanks for the help

 

I don't know about the late 80's ones but the 73-87's had a weak frame around the steering box and had a nasty habit of cracking. Look behind the box on the inside of the rail. There are 3 or 4 kits on the market to gusset that area.