Power problems

[1985 K10 Warhawk]

Long back story... If TLDR: Can skip to paragraph 5/6 for my questions
I recently purchased a 1985 suburban 1/2 ton with a carbureted 305 motor for a reasonably priced 1,140 (after a bit of haggling and what not).
Odometer reads 55k, the previous owner of 10 years put about 23k miles on it based off receipts, so I'd assume 155k miles on her. The engine doesn't stutter or sound weird and it passed emissions on its first try with no adjustments.

I really like this rig and was not raised in a very mechanically savvy family. I purchased it with the express intent of doing most of the work myself to learn. After reading ck5 and pirate4x4 for a few months, I budgeted a little extra money to make the purchase. I knew I was buying a bit of a heavy junker, but I like the look. Will be adding more pics when I get home from work today as long as the sun stays out!http://www.pirate4x4.com/forum/chevy/1768625-1985-suburban-project.html


...Then I blew my projected budget on it at an offroad shop having them 4' pro comp lift it, replace a twisted axle, redo all the bearings and bushings, (5) new 33' BFG ATs and (5) 16x8 new pro comp D window matte black aluminum rims, 2 new window motors, 2 new door lock solenoids. The guy would call with minor fixes and quote a little bit more, then I picked up my truck along with a 5600 dollar bill.

It served it's original purpose of driving me and 8 other people the 350 mile round trip from Boulder to Glenwood springs. And well, I felt safer knowing a shop I trusted made sure the steering and front end were in good working order. On Flat/slight uphill/downhill she moves and will get up to about 65-75 MPH.

While making the drive, I struggled getting the beast up some of the mountain roads. If I had her in OD, she went no where. If I had her in Drive, she maybe got to about 35 MPH (In a 75!), While being slowly passed by Semi's with full loads. I dropped her into 2nd (60ish MPH) and the engine was screaming along with the 3rd row heating up (...assuming the tranny was running a tad bit hot) So, what do I do? Is she just so heavy, weak and old that she cant move mountains or where do I start to try and diagnose? Would a basic tune up help a lot? Like changing out spark plugs / flushing all fluids and replacing with new? Would the drastic elevation change be effecting the carb so much as to starve the engine?

She leaks a little bit of oil near where the tranny and engine meet (maybe the size of a quarter after 2-3 days of sitting) Do I try the lucus oil seal sealer? Also, with the 4' lift, how am I supposed to jack up the vehicle to work underneath it, do I need a special jack or will the 80 dollar Costco one be fine?

The intent of this was to be my trail rig (nothing overly serious, I'm new to trail riding as well.. but did have fun the 2x I've went.. even had her near side ways crawling through mud.. exhilarating!)

Ideally yes, I would like a fuel injected new or slightly used 350 motor out of a wrecked truck.. but that is a bit of an undertaking with some one possessing no tools (other then a basic socket set) and minimal knowledge at the moment. And at this time, I haven't made a local friend yet who is *that* mechanically inclined (recent transplant to Boulder, CO). My neighbor seems to know a thing or two about working on his Cherokee, but I haven't asked him for help yet.

 

[dyeager535]

What are the gears in that thing? I don't know what 1/2 ton burbs got, but the K5's got 3.08's that vintage, and they sucked for power. 33's are going to exacerbate an issue with gears. Not that it will be correct, but what are the "G" codes in the glove box? GU4, G80, etc.

On one of these trucks I wanted to get more power out of, if the gears were even 3.42's, 3.73 or 4.10's would be the first thing I did. Swapping complete axle assemblies isn't that tough, and 1/2 ton stuff is pretty cheap. Of course, for trail stuff, at least the rear isn't likely to hold up if you are hard on it, and the 14SF is a big upgrade, but a tougher swap than 1/2 ton axles.

 

[1985 K10 Warhawk]

and



After reading that, it states that I have the 5.7 liter v8, the last owner told me it was only the 5 liter 305! I did not know that card even existed. Thanks for the tip. Gear ratio is 3.42 (1GU6)

She just feels like such a dog on hills. Also the engine just started backfiring last night (The fuel is about 3.5 weeks old in it right now too though)

Sorry for such a delayed response on the apply. RL got in the way for a moment there!

 

[paratrooper307]

If it's backfiring, that could indicate a timing/ignition/fuel/valvetrain problem that is costing you power. 3.5 week old gas is plenty fresh as long as it hasn't been contaminated.

While those old 350s are going to be dogs moving a heavy loaded Burban (I think stock power was around 160) you'll want to make sure that you've got it tuned as well as possible before you start throwing money at it. A basic tune-up and fluid changes should be part of any truck purchase, to eliminate unknowns and eliminate the easy problems and get a good foundation. A compression and leakdown test can tell you a lot about the internal condition of the engine, and they're easy to do. Wouldn't hurt to pop off the valve covers and make sure the rockers are adjusted too.

Make sure your transmission cable is adjusted properly, if it isn't downshifting when it should it will feel doggy.

I'd avoid putting in the sealer gunk if you can avoid it. Such products are unlikely to fix the problem. Find out where it's leaking. Might be a rear main (common on the two-piece seal motors) but it could also be oil dribbling down from the valve covers (also common) or slowly leaking from the oil pressure sender fitting (what happened to me).

With a 4 inch lift and 33's, you won't need to jack up the vehicle to work under it, unless you're doing something that requires tires off the ground. I have the same setup and I just put a jack with a wood block under the diff and lift it when needed.