Re: 1968 GMC - Ol' Blue
 

Thanks. It's pretty loud, so I feel like I have to keep my foot out of it most of the time since I'm driving by houses most of the time. I love the truck, but it's nice to have a 2016 that is quiet and comfortable so I can switch back and forth between trucks.

I plugged in HPTuners the other day and fuel trims all looked pretty good but I could probably calibrate the MAF.

Thanks. You'll be there soon enough. One day at a time is all I can say. The details you're doing with your cab are going to look great.

Thanks!

Re: 1968 GMC - Ol' Blue
 

Lessons Learned

I've learned a few things on this truck that I wanted to let everyone know about so that maybe you guys can avoid some of the hassle I've dealt with:

-Install fender emblems before mounting the fenders, because it is almost impossible after the fact. I actually threaded the studs on the emblems and used a rubber washer to keep the emblem from contacting and scratching the paint and use a nyloc nut on the backside with a washer.

-Install plugs in the front end of the outer rockers before installing fenders. Same struggle as the fender emblems, very hard to do after the fact.

-Go with the Boyd tank. Don't mess around with anything less.

-If you're using rubber fuel hose, use Earl's Vapor Guard and their fittings. Easy to assemble and no fumes in your garage. On the same token, go for the WIX fuel filter/regulator if you're doing an LS swap. The cheaper units like to leak.

-If you end up with a leaf spring truck, just know that everything is going to be harder. Leaf spring trucks are an oddity and the aftermarket support is not as great as a coil truck and leaf spring trucks are harder and more expensive to lower. If I could have gotten a good deal on the back half of a coil truck, I would have swapped it. I saw a complete chassis on FB marketplace for $100 but it was sold in an hour.

-Hydroboost is awesome. Do it.

-You get what you pay for when it comes to electric fans. If they seem too good to be true, they probably are. There is a lot of false advertisement out there on CFM ratings.

-Make sure you get the wiper linkage put on correctly before closing up the cowl and installing wipers. It can be put on wrong and your wipers will be all messed up and you end up struggling to get the wiper arms back off after you've scratched the paint.

-Rectorseal 5 seals up a myriad of fluid leaks. I used it on an NPT fuel fitting leak, an NPT oil bypass plug, and an NPT brake line fitting.

Re: 1968 GMC - Ol' Blue
 

Thanks for the advice Potter. The one on your list that's got me thinking is the hydroboost brakes. I've already purchased the new parts for a standard power disc brake set up but I'm considering changing over before I install anything. Can you recommend any threads that you used to guide you through the parts needed?

Re: 1968 GMC - Ol' Blue
 

Love the lessons learned post, and I agree with all of it. Especially the hydroboost and Boyd's tank :)

Re: 1968 GMC - Ol' Blue
 

I love the lessons learned idea. I was just thinking about those rocker plugs the other day and realized those need to go in before the fenders go back on. Agree on the Boyd tank for sure...in fact, whenever I tried to go cheap it usually ended up costing more in the long run. Great build and great advice.

Re: 1968 GMC - Ol' Blue
 

For sure. A few pieces of advice from me:
-Not all hydroboosts are the same. Gold accumulators are for front disc/rear drum applications and silver is for disc/disc. I bought a unit off a 2008 Duramax at the junkyard and ended up selling it on Facebook at a loss because they wouldn't take it back.
-The unit develops a leak after awhile and from my research it's where the case comes in half - there's a big o-ring there. I took mine apart and put in a new one and haven't had any leaks. I got the kit from Pirate Jack (Google it) and was like $30. Sucks to pay that much for just the o-ring and have all these unused parts, but it's better than having a leak.
-Apparently hydroboosts are pretty universal in terms of parts because there are only two rebuild kits out there.
-There are lots of options for hoses. I have a lot of detailed info in my thread about what I did.
-There is very little clearance between the inner fender and steering gear, so the fittings/bends have to be really tight there.
-I fabbed up a custom firewall mount that bolted up to the brake assembly studs.

Here are threads that I read through that helped me:
http://67-72chevytrucks.com/vboard/s...d.php?t=523502
http://67-72chevytrucks.com/vboard/s...=768975&page=2
http://67-72chevytrucks.com/vboard/s...d.php?t=733949
http://67-72chevytrucks.com/vboard/s...d.php?t=347480

Re: 1968 GMC - Ol' Blue
 

I second this. I actually ended up cutting part of my inner fender around the fittings to make enough room. I'll make it pretty come body/paint time.

Re: 1968 GMC - Ol' Blue
 

So, the one I have from the Astro van is not going to work now that I have the Wilwood disc in the rear? Oh boy...

Re: 1968 GMC - Ol' Blue
 

I bet you'll be fine, they just don't put out as much pressure from what I understand. But it's not like these are heavy trucks and the rear brakes don't do near as much as the front. Here's a link, scroll down about halfway down the page: https://www.hotrodders.com/forum/hyd...20the%20spring.

Re: 1968 GMC - Ol' Blue
 

MD Potter,
VERY VERY NICE!!! CONGRATS!!.. it looks really good. glad to see it finished. when i finished my '72 a few years ago & took it on it's maddon voyage I was smilin' from ear to ear!. the best thing is the road recognition that comes with driving a "cool truck". please give us a few updates as driving is more normal for it...
again... congrats!!!:metal:

...:devil: :cf:

Re: 1968 GMC - Ol' Blue
 

Congrats on finishing and thank you for posting the lessons learned!!! We should make that a tradition for every build that is nearing the (temporary) end.

Re: 1968 GMC - Ol' Blue
 

Congrats MD, truck looks killer! I never replied but thanks for the info on the sub box. I had to modify a little bit since my shallow mount required .8 cu ft of space but the design was perfect and my seat fits well now.

Re: 1968 GMC - Ol' Blue
 

MD Potter,
Hope you are well & having fun driving around a cool truck!!. I re-read the thread & didn't see how you hooked up the trans linkage? I am wondering how you connected the shift linkage on the trans to the truck column? I am tryin to figure out on my build now... LOL!!!

thanks!!

Re: 1968 GMC - Ol' Blue
 

I used the linkage kit by CPP. It's basically a rod with a clevis on each end. I didn't take any length out of it, but I did put a slight bend in the rod. It comes with the hardware you need to connect to the column and to the transmission gear selector shaft. It's part# CPTSL.

Re: 1968 GMC - Ol' Blue
 

mdpotter,
thanks!, the CPP kit appears to be very similar to lokar. I was hoping to use my original linkage and save the $80-90. it is looking more like I am going to have to make "the shift" :lol: and get a kit...:waah:

Re: 1968 GMC - Ol' Blue
 

I used the lokar kit. And I did the exact same steps as Potter. :thumbs:

Re: 1968 GMC - Ol' Blue
 

Just a quick update on the truck:

-Sway bar is on backorder, who knows when it will come in.
-Alignment is done but it's still got a shake at certain speeds so I'll have to get the wheels and tires checked for balance.
-The low-beam filament on one of my outside headlights went out, so that's kind of disappointing considering how little I've used the headlights. Probably just cheap bulbs that came with the headlights.
-It started running pretty rough under light acceleration the other day so I've been working on diagnosing the issue. I have been doing some tuning which has been fun but those steps haven't fixed it nor the other things I've checked. Other than that, it runs great.

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Re: 1968 GMC - Ol' Blue
 

Gotta love all that chrome on the front of the gmc's. Looks like you will be having a ton of fun in very short order with this truck. Great build

Re: 1968 GMC - Ol' Blue
 

I was out on a tuning drive a couple weeks ago and stopped to take some pictures as a storm was rolling in. A few updates:

-I replaced the generic MAP sensor with AC Delco and it seemed to help but hasn't eliminated the problem. It still runs a little rough under light acceleration once warmed up, but only once in a while. Not done tuning yet though. Still have to get into timing, but it runs pretty good - 0-60 in 5.4. It's really slow off the line, but it really pulls once you get into the powerband. I have a 12-bolt with 4.11 gears to swap someday which will help with acceleration. My 3.54 rear end is a little high since I don't get on the interstate with it.

-I have a sway bar and new front coil springs to install one of these days. I regret chopping another 1/2 coil off my springs so I bought new 1" drop to get me back where it was.

-Someday I'll get Vintage Air. Been spending money on wedding stuff.

-The reverberations that I feel/hear are still there at certain RPM's. I might try replacing the rubber engine mounts with nice poly mounts and see if it makes a difference.

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Re: 1968 GMC - Ol' Blue
 

The vibrations at certain rpm's makes me think the driveshaft angles aren't matched. I don't remember how much you dropped the truck, but you may need a shim for the rear end?

Re: 1968 GMC - Ol' Blue
 

I hadn't thought of that, but I don't think that's it because I've felt it at speeds less than 10 MPH.

Re: 1968 GMC - Ol' Blue
 

Fantastic work, and Great Lessons learned. i just finished my 3rd one. Not for nuthin', what'd you do with the old tailgate?

Re: 1968 GMC - Ol' Blue
 

I still have it, do you want it? It's the small GMC letters.

Re: 1968 GMC - Ol' Blue
 

Check out the video in post #3

https://67-72chevytrucks.com/vboard/...d.php?t=719912

Re: 1968 GMC - Ol' Blue
 

I do need to check my output shaft angle and pinion angles. I have a shake right around 40-50 MPH and it shouldn't be the alignment or wheels/tires.