Front lifts that relocate the differential

[Rinkrat456]

Let's talk crew cab lifts and 30.5" tires.

Today I mocked up a spare 245/75R16 to see how much more height I'd need to clear the tire compared to the current 235/75R15's that are on the truck now. I figured another 2.5" of front lift would be needed along with some minor trimming at the corners. Granted, this was a load range E tire from my uncle's truck that I tested with and I'm planning on running P245/75R16 Michelin LTX A/T 2 standard load tires for this daily driver, so I may not need as much trimming as with these 10-plys.

Anywho, the biggest issue when swapping in an LS-engine into 4wd S-trucks is the front diff and oil pan clearance. Originally I thought about installing a body lift and cranking the torsion bars a hair to get my 2.5", but what I really need is more room underneath the engine for oil pan room. What is available for 4wd's for lifting the front 2 or 3"? Also, what are you guys doing about the increased tie rod end angle?

If I can't figure out an extremely reliable way to lift the front, I'm just going to gut the IFS and toss in a Dana 30/Ford 8.8 combo lol, so let's not allow that to happen just yet. My wife would kill me if I did that....though, I do have a pair of matching Dana 44's with 4.30's and limited slips that I took out of my '96 Sonoma just waiting to go into something .

[HenryJ]

Check out the Blazer install with the 2.5" RoughCountry lift
I don't think it adds much clearance since it mainly angles the diff , more than dropping it much?

I think the SFA is going to be the direction to go. The stock 7.25" differential is not going to like a V-8.

[Rinkrat456]

I have faith in the front 7.25" and GM 7-5/8 rear 10 bolt with mild tires and a stock 5.3L. For a daily driven axle it needs to hold up to high speed long distance trips with proper lubrication and good bearings. If, for example, I was off-roading this truck or street racing it, I'd be more worried about the shock loads to the axle shafts but I'm easy on my daily drivers so it should be fine. I'm in 2HI most of the time and the rear axle's nearest cousin, the Dana 35, is commonly found behind Jeep 4.7 and 5.2L V8's with 30-31" tires from factory and that's a 7.5" axle with 1.09" 30 spline shafts. If something does blow up, rumor has it the ZR2 axle fits nicely. The front diff has been known to handle tremendous stress from Syclones and Typhoons so it's the axle shafts I'd be worried about.

I just read through the thread you linked...I see the wedges you're talking about. That's a step in the right direction but I'm in need of more spacing. As easy as a linked D30 swap would be, I think I'm going to try to tough it out and keep the IFS in there for this truck. Hmmm...

[HenryJ]

I think you will find with a little more research, that the stock differentials are not particularly suited to a V-8 and they are marginal for a healthy , stock V-6. The rear is flexy and the front fragile. Upgrading to the ZR2 rear axle is a must in my book. There is a HUGE difference.

The 1/2T GM IFS has been done, as has the 9" Ford / Porsche but any IFS mod is going to be more $$ than a SFA.

[Rinkrat456]

When you say "the front fragile" are you referring to the aluminum housing or to internal parts? Any experience busting things up?

With the front IFS crossmembers cut out, one could retain stock ride height and 31's with a Dana 30 front and long arms...but I'm convinced there has to be a better solution with the IFS when discussing the future of a daily driver. More research and long hours of staring at the front suspension are needed.

[HenryJ]

When you say "the front fragile" are you referring to the aluminum housing or to internal parts? Any experience busting things up?

Both. I have not trashed a front myself, but I don't push limits. No way would I saddle that little ring gear with a V-8 sitting on it though.
I have had a fleet truck puke a front and seen several others do so. Too much skinny will make them do that in a hurry.
It is not just the increased torque that will pose a problem, it is the weight added too.
I don't like to ride the edge too close. A mall crawler that is very careful , might do just fine. Not my style though. I prefer functionality and durability.

[Rinkrat456]

I'm easy with the skinny pedal for daily drivers. The aluminum 5.3 is also lighter than the 4.3, so as long as I keep my beer gut in check this truck should actually lose weight.

I'm going to keep the axles the same. Putting your truck in 4LO actually puts more torque to the axles than dropping a 5.3L between the frame rails.

[HenryJ]

... Putting your truck in 4LO actually puts more torque to the axles than dropping a 5.3L between the frame rails.

Apples and oranges. Gear reduction does not multiply or increase the engine torque it reduces the torque required to move the drivetrain

That said if you have the traction and want to tear things up, it can be done.

The 4.3L already has heating problems. The thicker radiator helps, but at altitude it is not enough. How do you plan to keep a V-8 cool. Mike had issues with his LS engine. Electric fans on both sides. (BTW, he trashed his 1/2T front axle. Nothing is bullet proof. )
The grille openings are small on these. That is going to be a challenge.

[paintballrocker]

if you go sfa your going to have no problems dropping in a v8 and you will have a suspenion that will hold the power. IFS with a v8 is crap

[HenryJ]

... IFS with a v8 is crap

I know that you don't include that as a blanket statement IFS has its place
I am a firm believer in IFS for a daily driver and high speed offroad performance. I am just not for pushing beyond design limits. Those limits have been tested and proven to me in this case.

The 4L60E transmission has been offered OEM behind a V-8, the transfercase (manual or Auto) has too. The 8.5" rear axle? Yes. The D30? Yes. The 7.25" GM IFS front? NO.

[Rinkrat456]

Apples and oranges. Gear reduction does not multiply or increase the engine torque it reduces the torque required to move the drivetrain

I totally agree with you in part....that gear reduction requires less engine torque to move the drivetrain. You are absolutely correct. Most folks think of gear reduction in terms of torque multiplication...which suits the masses... but in fact the low range of the transfer case simply makes it 2.72 times easier for the engine to move the vehicle. You can't stop the train of thought right there though, because the t-case also makes it 2.72 times easier to break parts. Every axle shaft I've snapped, every transfer case I've cracked and every drive shaft I've twisted all happened in 4LO. I've spent thousands of dollars fixing or upgrading my 4LO wheeling lol. I'll bet top dollar a 4.3L V6 in 2:72 4LO is more of a lethal weapon against drivetrain parts than a 5.3L V8 in 1:1 4HI. I wheel with guys who have the 4.3L turning all four locked 46" bias ply tires and it's easy with the proper gearing. Even I have had the pleasure of wheeling with both engines (my '96 had a 4.3L, 5.3L and now a 5.7L) and the 4.3L has no shortage of low end torque...what it lacks is technology and that's one of the reasons I got rid of it.

That said if you have the traction and want to tear things up, it can be done.

Absolutely...that's what my '96 is for. My 2002 Crew cab however, is a pavement and gravel road machine...and only sees 4wd use when the roads are slippery.

The 4.3L already has heating problems. The thicker radiator helps, but at altitude it is not enough. How do you plan to keep a V-8 cool. Mike had issues with his LS engine. Electric fans on both sides. (BTW, he trashed his 1/2T front axle. Nothing is bullet proof. )

I will keep the 5.3 cool in the same manner I keep my '96 Sonoma and iron block LS1 cool. Ditch the factory 4.3L radiator, push the A/C condenser forward and put a large all-aluminum dual core radiator into the core support. F-body fans on the backside pull plenty of airflow when properly shrouded to keep the engine cool on just low speed, but I'll have the PCM monitoring temps in case high speed is needed or whenever A/C is activated. An aluminum block and heads sure helps with cooling also...you'd be surprised. In addition to engine cooling, most new truck engines are coming with engine oil coolers which I fully intend on implementing, along with an additional trans cooler.

The grille openings are small on these. That is going to be a challenge.

They sure are! The plastic baffles directing airflow through the grille opening and into the radiator/condenser are more important than most V8 guys think.

[Hartleybl]

According to aam the 7.25 was used under v-8 vans you can also purchase the cast iron differential directly from them for 339.00 I know this is an old thread but.. Maybe someone lurking around here will find this useful