03 GMC w/H2 wheels & tires

[Jelisfc]

Pics are posted, see my sig.

Green keys up front and 2" blocks in the rear. The keys went in without a hitch and a relatively small gear puller, (be careful though). The front went up 2 3/4" by switching keys with the adjusting screws in the same spot. Initialy the front was pretty stiff. I have a R/R crossing I use as my worst case scenario. The front wouldn't even give going over it. This weekend I made 1" thick aluminum spacers below the lower shock mount. The ride is much improved. A tad stiffer than stock but that's expected. My R/R crossing is much smoother now. I would recommend only a 3/4" spacer because the half shaft is close to the shock bolt now but doesn't hit.

The 2" rear blocks went in easy...after I figured out the spring bolt head was too large and I drilled out the block holes. Shocks seem OK and the ride wasn't effected. I've had the 2 pc drive shaft shudder just never really noticed since it happened while letting the clutch out. With the bigger tires I now let the clutch out THEN get the shudder. The final phase of this project will be to experiment lowering the carrier bearing to reduce this as much as possible.

The tire setup is great. Barely any road noise. Holds corners well. With the ZF I like the lower effective rpms. I don't find myself reaching for 7th gear anymore. ;) Going to Fargo this week and I'll be checking mileage via GPS. Normally get 21.5 to 22+ highway.

Trimmed the airdam 1 1/8" in on the bottom going upward to zero. Approx 7 1/2" from top of air dam is where I stopped.

Overall I gained 4 1/2" in the front and 4 1/4" in the back.

Thanx to everyone here who has posted. The tire swap and Cat filter install where two of the easiest projects. Not one wrench thrown. :D :D :D

[mfontana]

Jelisfc Truck looks great! What will you do for a spare? Great job with the camera. Everything was well lit.

[mfontana]

Jelisfc Truck looks great! What will you do for a spare? Great job with the camera. Everything was well lit.

[Uncle Dimmy]

Jelisfc,

I have the keys and 2" blocks on my truck, running 315/75/16 tires as well. I have gotten rid of most of the driveline shutter, but the front end is, like you said, much more rough than stock. I've even considered taking off the lift due to the ride at times, but hate to as the truck looks very good now.

I see you put in the 1" spacers for the shocks and I also see that you have the stock shocks still in. I see that you said the ride is much improved now, but why did you choose 1" instead of the full 2" to get the full travel back in the shock. I also see that you said you should have only gone 3/4", why do you say that?

I'm curious and plan on doing this spacer idea in the next day or two. I'm looking for some insight to what you did.

[Jelisfc]

mfontana, The spare will remain a 245. If I blow a rear I'll just have to switch two tires.

Uncle Dimmy, You can't raise the shock 2". The block moves the shock out at an angle and towards the spindle. You'd have to figure out the suspension geometrically to determine what would restore the shock to its unlifted state. The bottom of the shock due to the angle is moved outward and that gives the shock move leverage against the A arm. I recommend a 3/4" spacer because 1" puts the shock nut close to the half shaft.

I removed the lower shock bracket. I had 1/2" plate so I made four pieces 1 1/2" x 3 1/4". Marked and drilled two 13/32" holes to match the bracket. Reinstalled using M10 x 50mm bolts and lock washers. Make sure you get 10.9 hardness DO NOT use 8.8 grade!!!! 10.9 equals grade 8 SAE and this is one place with the extended length you want to skimp. The shock bolt won't feed from the front after so I reversed the bolt so the nut is on the front side of the mount. The biggest PIA was to compress the shock and hold it up with one hand while wrenching with the other.

I am happy with the way it rides now. I have no plans to change the setup.

[Uncle Dimmy]

Thanks Jelisfc! After I posted my reply to this topic yesterday I went out and looked at everything real close myself. That's when it came to me that you used square blocks and the bottom of the shock was being kicked out and that was the reason for only 1".

I own a fabrication business and we have a full fledged machine shop. I'm considering figuring out the correct geometry for the spacer, milling it to the correct angle, therefore, putting the shock back in the exact same position it was from the factory.

I am also very aware of the hardness needed for the bolts. After I figure out what I am going to do w/the spacer, I will be getting me some longer bolts. I'll try and keep you posted with my results.

Thanks again.