I have a truck but I thought you guys would be more LS knowledgeable than a truck forum.

I have a 2012 Silverado with 4.8L LS V8. I want to install a 5.3L crank and rods but don't want to disassemble to top of the engine to do it. The engine has 40k original miles and has been babied so I'd rather not break it open anymore than I have to. Has anyone been able to get a rod out of the bottom of their LS? I figure not but I thought I'd ask and maybe get lucky. If not I may just wait and drop in an 6.2L when I save enough money.

 

No.

Pistons won't come out the bottom, and there's no way to get the wrist pins out while they're in the bore.

 

I knew the pistons wouldn't come out but maybe far enough to slide the pin enough to pull the rod. Thanks for the info.

 

Leave the 4.8.
The 4.8 will outlast 3 transmissions, and will likely still be running after the 2012 truck rusts away.
IF it doesn't PULL hard enough: Re-Gear appropriately. Short stroke motors like to REV.
My 4.8 spins HAPPILY with 4.56 gears.
If the correct GEAR ratio doesn't get you enough fun: add manifold pressure.
I am limited by 90 Octane fuel here, but 11 PSI boost is plenty to shred 12" wide tires.

 

Nope.

 

The problem is towing. Even with a light load it struggles. If it had a 6L80 with lower and closer gears maybe (I have the 4L60). I thought about changing out the 3.42 gears for 4.10 but decided to not mess with the 8.25 IFS front. Unloaded even at 5300lbs it gets up and goes but once on the highway it hates the wind resistance of even a 7x14 cargo trailer above 50mph. I sold my 6000lb travel trailer because the truck wasn't even close to handling it at highway speeds. I would love a 4.8 in a camaro but my truck needs the stroke. I've driven a lot of 5.3's with 4l60's and the same ratio and they do not struggle at all. If I do the swap you better believe I'm saving the crank and rods for a 6.2 block and turbo. It has 302hp/305ft/lb but it doesn't translate well for towing with highway gears.

 

If you step back and think about it, this is the only real answer. I don't honestly think you'll be happy with a 5.3 either...

 

Gears are a huge deal. That 8.25 front end is not too bad honestly. You can have it out of the truck in an hour, and you get to re-gear it on a bench…no hurt back or hard to see stuff. Pretty easy really.

 

My buddy has a 4l60 with a 4.8 in his truck and he makes a living towing with it. he tows whatever someone will pay him to haul. I tweaked the tune and built the trans for him. We put a higher stall converter in it (maybe 200rpm higher) and he has 3.42 gears. He towed my car once when I was riding with him and it pulls np problem. He said the tune helped a bunch. That may help you. You shouldn't be struggling to pull a light load.

I had a 99 5.3 truck, 212/218 cam, trailblazer convertor, 4l60, headers and 4.10 gears. I pulled a 7800lbs camper with it. it did just fine. I don't pull over 65mph, but it pulled at 70 no problem except sway.

My advice is either:
1) leave the 4.8 and put a turbo on it, smaller sized will pull better
or
2) if you are going to motor swap, skip the 5.3 and do a 6.0 so you won't need to worry with gears and whatnot.

my vote is a turbo. No cam, no gears...just a turbo. 3-4psi will work wonders for towing. The cool thing about a turbo on the 4.8 is your gas mileage won't suffer as long as you stay out of boost. The cruise/idle fuel mileage of the 6.0 or 6.2 is going to be more than the 4.8 at cruise or idle

 

I don't like the way you setup that 8.25 IFS clamshell. I just don't think you can be sure it's right. When I'm back in Alaska I will be doing 75mph in four wheel drive in the winter. I'll go back and watch a few videos again. I was actually thinking about trying to find a salvage unit and then doing the 10-bolt rear myself. Bumping the cubes for now is just cheaper and easier.

 

75mph towing? in 4wd in the snow? Thats mind boggling how unsafe that is.

 

Haha! No ice road trucking at 75mph. Lowering gearing means I have to replace the gears in my IFS front diff and because of the design I don't feel comfortable using a diff I rebuilt myself or someone else for that matter. When I'm in Alaska the speed limit is 70mph on the highway and if the roads aren't dry you are in four wheel drive. Hate to have a diff lock up then. If I was towing I would be going 60 and only when conditions are safe.

 

Watch a video. It sets up like a Corvette diff or even a quick change rear in a circle track car. Not too hard at all. It’s different, but not hard.

 

If I go 5.3 I only need a crank, rods and of course gaskets and head studs and drop in a stock 5.3 tune. If I go any bigger or turbo I'll need to beefcake the trans. Stroke is exactly what it needs. Down the road it will get a turbo and possibly a 6.2. If the truck had more miles I wouldn't feel so bad about redoing everything. Che70velle is making me thinks I might be able to handle the front diff.

 

I will do that. I guess I'm getting paranoid with age. 20 years ago it would have already been apart before watching a video.