Just bought a 79 GMC
 

:gmc2: Well Bought a 79 GMC 4X4. Doesnt need much... its going to be my daily driver. Even though gas is 3.15 where i live right now. My question(s) is i want to beef the tires and possibley the rims a bit. BUT i dont want to go huge lifted up monster i just want a nice stance with some beef to em to, i dont know "stabilize" the ol' girl a little better. She's just a half ton with manual lockouts so i guess my question is what would you guys recomend as far as tire/rim size to give it a bit more umph :bann: without going overboard...

Also since this is going to be a DD. I was wondering cause i havent done much research on it, but have heard the 'romors' for a lack of a better word. But does changin the exhaust help out with MPG's and i was thinking of a K&N air filter... obviously not a bad idea anyway.. but any more sugestions on the MPG increasing problems?

Sorry no pics as of yet. hoping to fix us a few rust spots, then paint her.
two tone black and metalic camel (stock color)

Re: Just bought a 79 GMC
 

You are wanting something thats not feasable. Better MPG and bigger tires don't go together. Regardless, I think 33's are a great size tire for these trucks. Before you change tires, figure out what gears you have. If they are high like a 3.08, your MPG will suffer.

Re: Just bought a 79 GMC
 

I was more thinking of just wider... not taller.. MGPs still suffer then?

Re: Just bought a 79 GMC
 

MPG's will suffer due to the added weight. You're not going to gain any mileage from one of these trucks if you modify the tire size. But for the stance you're looking for, are you willing to do a small lift? A 2" lift with 33x12.50's looks just right. A little more aggressive, but not crazy. A 2" lift shouldn't be that much.

Re: Just bought a 79 GMC
 

Not sure if i want to lift at all. I agree with you that the stance and lift you talked about looks really good. but im more interested in just changing the tire and rim size. As for the MPG's im not ignorant i know these things arent awesome but there are things that can be done to help out. Shouldnt not do something cause its not going to DRASTICALLY change it. Every little bit helps so that was why i asked if exhaust systems helped out. And maybe which ones were better for the MPG, if there is such a thing. Also changin the air/fuel mixture with after market air cleaner, or a simple carb clean/tune up. Thats all I was askin in reguards to that.

But with the tires/rims/suspension. I just wanted something a little bigger as far as width, not really taller. I guess i should go to a local rim/tire shop and see what they say. Maybe they'll have something that'll fit just right

Re: Just bought a 79 GMC
 

The biggest you can fit on a stock height 4x4 are typically 285/75/16, it's about a 33x11.00 for a 16 inch rim. I think it would look good on 8" wide rally's if yours is a half ton, or some kind of of nice aluminum rim if yours is a 3/4 or 1 ton. I wouldn't go with any wider of a wheel unless you carefully check the backspacing, that might cause them to rub. I ran an 8" wide aluminum rim (I have no idea who makes them) with 285/75 R16 Cooper STT's on my truck before I lifted it, and if the truck were any color other than orange I would have loved it. Here's some pics for reference. The first one is with the Coopers, and the other two are with some bald tires of the same size that came on the truck when I got it.

http://img217.imageshack.us/img217/7739/chevy9.jpg
http://img703.imageshack.us/img703/6383/chevy4.jpg
http://img40.imageshack.us/img40/7540/chevy72.jpg

Re: Just bought a 79 GMC
 

Your41.... so that has no lift to it at all? just different tires and rim? Cause if that is no lift that is a great stance to me! I just dont want to lift it. I like stock height just not the stock tire size. I like your truck.... Orange and all!

Re: Just bought a 79 GMC
 

http://i141.photobucket.com/albums/r...downsize29.jpg

http://i141.photobucket.com/albums/r...ownsize9-1.jpg

A comparison, this truck has 31" tires and 15" rims. It has a add-a-leaf in the back.

Re: Just bought a 79 GMC
 

Come on man, that color is awesome, change your user name to The Great Pumpkin and run with it. Those are the same size tires I plan to run on my 4x4 Burb with no lift, an 8" rim w/4" BS, looks real good. No rubbing?

Re: Just bought a 79 GMC
 

So what size can i get away with without a lift?

Re: Just bought a 79 GMC
 

Looks like we don't want to go bigger than 33x11.5x15 or aprox same size for a 16" rim 285/75/16. As your41plague12 stated, that is what he was running before he did a lift. You would probably get away with 33x12.5 if the BS was right, but the wider tire= more contact patch= more friction= less mpg.

Re: Just bought a 79 GMC
 

we ran a 33 12.50 on a 15x8 rally on the 86 we had all stock no rubbing anywhere. it was a short bed 4x4.

Re: Just bought a 79 GMC
 

I had 33x12.50's on it once and it rubbed the back corners of the fenders at full lock. The 285's eliminated that. And to the OP, no, my truck was not lifted; totally stock height for those pictures. I'd go with a set of 285/75/16's and some nice wheels and call it a day. I only noticed like less than 1 mpg in difference between the coopers and the same sized street tires. I highly recommend them if you drive in snow at all, that seems to be where they excelled to me. They have almost an identical tread pattern to a BFG Mud Terrain, but the side lugs are more aggressive and they're much cheaper. Gotta run the white letters out, too :smoke:

EDIT: and if you liked how it sat there, for ****s and giggles, this is how it is now:
http://img842.imageshack.us/img842/7...29101404b1.jpg
http://img809.imageshack.us/img809/4...229101404a.jpg
http://img823.imageshack.us/img823/9...1229101404.jpg
http://img403.imageshack.us/img403/4...227101328a.jpg

It's funny you mention the name "The Great Pumpkin," too. People around here either call it that or "Orange Crush." I like them both, but my girlfriend is hooked on calling it "The Pumpkin." I guess that's what it shall forever be, now.

Re: Just bought a 79 GMC
 

Well that is one badass pumpkin, I prefer the new look myself. Leatherman, when do we get to see some pics of you new ride?

Re: Just bought a 79 GMC
 

didn't I see that truck on fsc or another site?

that's weird though cuz ours never rubbed anywhere.

Re: Just bought a 79 GMC
 

I ran 31x10.50x15s with no lift, no rubbing at any time. Installed a 4" lift and 35x12.5x15s with the stock gearing and diddn't like the way it handled and lost too much power so I downsized to 33x10.50x15s. Diddn't care for the look as much as the 35s but they deffinatly handled very nicely for a dd and hunting truck.

here is a couple pic's with the 35's and 33's.

Re: Just bought a 79 GMC
 

soon my friend soon! :metal: I appreciate all the help with the rim and tire situation... I dont "mind" the little guys that are on there. But it looks more fitting to be putting something bigger on there. Hell the tires from my 69 might work! haha

Re: Just bought a 79 GMC
 

Benoit454, yes you did! I have the same username on both sites. And to the OP, I'd go with a 285/75/R16 on your truck. That will clear perfectly, won't rub, and won't rob you of power too much at all. Probably won't even notice the difference in power. The 33x12.50's are a little too wide for a non-lifted truck, and will probably rub like they did on mine.

Re: Just bought a 79 GMC
 

Sounds like 285/75/r16 might be the winner!! Does anyone have any info on my other Question? The "does the exhaust change MPG's for the better?" question. I've heard it does... just havent done the research and no personal experience either. So didnt know if that was an old timer tale or what.

Re: Just bought a 79 GMC
 

I always found that with a stock drivetrain an aftermarket highflow exhaust would improve mileage a little, but only on the highway. Around town the loss of backpressure hurt gas mileage. I will be replacing my rotted out exhaust with a stock spec. Walker system. The 6.2 is loud enough on its own, and I'm getting 24 mpg on the highway at 65 mph, not bad for a 6000 lb landyacht.

Re: Just bought a 79 GMC
 

If you're running a race motor, low backpressure is great. If you're looking for a streetable motor, having some backpressure is a good thing. It's nice to let a motor breathe, but when it breathes too much, it actually hurts your efficiency. If I were you, I'd delete the cats/emissions items (if you're able to, where you live) and call it a day.

Re: Just bought a 79 GMC
 

every truck is a bit different but we ran 33x12.50's completely stock on our 86 no rubbing at all.

I'm swims350 on other forums I thought I had seen it, awesome looking truck.