GMC truck questions and musings

Thinking about dropping my cheapo beater '88 GMC 1500 (2WD) just a little bit. Any reason I can't just flip the shackles in back and cut a half a coil or so off the front springs? Seems like it should be pretty straightforward - and free - to me, but what do I know?

Is there a junkyard go-to for a rear (and/or front?) swaybar for these things?

My 305 is kinda getting tired, so I'm beginning to think about engine swaps. A 350 is obvious, and likely the easiest, but I'm intrigued by the idea of putting in a mildly built and blown 4.3. Lighter, better mileage, comparable performance to a mild 350(?) - but would it be more trouble than it's worth? I should add: in keeping with the cheap beater theme of this truck, I can get my hands on a wrecked S10 with a 4.3 for a song, if that influences your judgement on the motor issue.

I'd look to the 1-ton version for cheap junkyard swaybars.

A shackle flip may lower it too much, but no reason you can't undo it if that's the case. Lowering blocks are cheesy, but work just fine for a daily driver.

The 4.3 won't get you better mileage, at least in my experience. My 3/4 ton truck never got better than 15 mpg with the 4.3, my friends Suburban got around 17 with the 350.

You can buy a replacement truck 350 for super cheap from either summit or GM.

Cant help you on lowering the truck. I need ground clearence on my trucks and have looked into lowering a full size truck.

i had a 90 with 3" drop front springs and 4" drop in rear with hangers and shackles. it rode like ass and had no cargo capacity before the springs hit the underside of the bed, but it handled nice for a fullsize truck.

No love for the 4.3? Good to know. I figured a 350 was the way to go, but the wild hare had me distracted. Of course, there's always a big block...

Pat touches on an important point: I do use this truck for hauling bikes and homeowner type junk like dirt and mulch, so I do want to retain its trucking abilities. That's why I'm interested in doing something as close to free as possible, and easily reversible.

If you do cut the coils, DON'T do it with a torch. Easy does it, with a saw or angle grinder. Keep heat to a minimum. Crawl under the truck with it sitting on all fours. Measure from one coil to the next, to get a rough idea how much drop you'd get from cutting one coil.

What does the pre-measuring tell me? If there's an inch between the inside of each coil, will I drop it about an inch by cutting one coil?

I was planning to go about a half coil at a time and see where that got me. I do recall some spring-cutting threads here, so I suppose I should start combing the archives.

The front is easy. One coil will give you about a 2" drop.

The rear is harder. You can get two inches from the cheap aftermarket drop shackles. To lower it more than that requires replacing the front hangers. Those together will get you 4". You can remount the rear end on top of the springs but that gives you about a 6" drop and requires the frame to be notched.

btp76 wrote: The front is easy. One coil will give you about a 2" drop. The rear is harder. You can get two inches from the cheap aftermarket drop shackles. To lower it more than that requires replacing the front hangers. Those together will get you 4". You can remount the rear end on top of the springs but that gives you about a 6" drop and requires the frame to be notched.

Nuts. I hate buying overpriced u-bolts and hunks of steel. Good to know, though. Thanks. Have a vendor recommendation for said overpriced metal bits?

Pick up some sort of sport truck magazine. It's been a few years since I lowered one.

Axle flip and lift shackles? 6" flip - 2" from lift shackles = 4"

Lots of misinformation on the 4.3's. Done right a 4.3 can do just fine. Both my 93 ECSB and my 89 RCSB got 23+ on the highway, about 19-20 in town. Sure, they were 17-second 1/4-mile beasts but they'd run 90+ all day long. For what it's worth, both were 2wd 5-spds with the 3.08 rear ends.

Shackle hanger kit and 2" drop coils will get the truck down, the 1.25" sway bar up front is fine, just replace the bushings and endlinks. Try to step up to at least a 255 width tire. The truck WILL handle decently. No, it's no miata, but it'll turn.

Bob, I think you're the guy that got me thinking 4.3s were good on gas. Would that advantage be a wash if I decided to build one to match the performance of a mild 350?

And I was planning on mounting a set of GM 15x8 rally wheels, which should accomodate 255 rubber.

Thoughts on a rear bar?

And I'm thinking a 3/4 drop would be about right for that wheel/tire combo.

4.3s are good on gas-in a light vehicle, like an S-10. I think you have to pour the gas to one to get it to move any thing with some weight. Thus negating the original idea.

^ Read 2 posts up. been there, done that, didn't bother with the t-shirt.

It all depends on the vehicle. I would suggest an L98 TPI 350 in a fullsize truck with an LSD on the 3.08 rear end. keep the rev's low, plenty of torque and plenty of power. That was my plan for my 93 actually before I got stupid and traded in a paid off truck in fantastic condition on a new Sonoma.

The 4.3 can be made as strong as a V8. turbo/supers make that a lot easier. Bone stock it's going to be slow. If you're OK with slow in a straight line they will reward with good gas mileage. If you want them to be fast they won'y be and you'll only be wasting gas.

alex wrote: What does the pre-measuring tell me? If there's an inch between the inside of each coil, will I drop it about an inch by cutting one coil?

You don't want to pull the coil out, see 4" between the uncompressed spring, cut a half coil out, thinking you'll get 2" and find that it dropped too much when you put it back in. Also, it saves time, instead of pulling, cutting, installing, "Damn, not enough." pull again, cut, install, etc.

Okay, so say I see 2" between springs (I'm pulling that number out of my ass, btw) and I want a 2"-3" drop. Do I cut 1 coil?

If you go cutting front coils, you end up with a shim stack like this to get it aligned properly:

I'm not a big fan of it...but you're right, it is cheap and it is done all the time, so it'll work.

My old '77 has some combination of drop spindles (which seem to be getting cheap-ish...maybe?), cut front coils and an aftermarket hanger/shackle combo in the rear.

Too low for me:

But it works alright...I even haul boards in the bed every now and then (that's ALL I do with it, really).

Clem

Oh...and that's the 15"x8" rally wheels with 235/75/15s, FYI... (missing a "beauty ring" in that photo).

Clem

Yeah, that's a little lower than I'm looking to go, but it's still pretty cool.

alex wrote: Okay, so say I see 2" between springs (I'm pulling that number out of my ass, btw) and I want a 2"-3" drop. Do I cut 1 coil?

Compressed, tires on the ground, normal load,etc... cutting 1 coil should give you 2" drop, in this instance. 1½ coil should give you 3".

I did this with my Sonoma, btw. One coil amounted to 2 and a small fraction.

And while I'm thinking it, the Sonoma/S10 axle is over the springs, so ghetto drop was $25 for blocks and shackles.

By your first post, I'm assuming the axle is under the springs?

Correct. C1500's are all spring over axle design.