Looking at getting a GMT800 3/4T Suburban, and a junkyard motor to do a full rebuild. Partly for fun, partly because I want a "new" GMT800 that will be good for another 300k or so. (I actually have an '02 1/2T Suburban but I want the 4l80 and 14 bolt).
I'm trying to get educated on which block model I should rebuild/drop-in. I know the Gen 4's are supposed to be stronger but I can't find a good answer on what was upgraded aside from rods and I think pistons. And would it be worth it, the gen 4's cost more up front and you have to convert the sensors over. There's enough info online, doesn't seem too hard to do. And probably do the DOD delete, and I think all gen 4 was DBW... I'd have to figure that part out I guess.

The other thing here, I'm trying to do an armchair build and consider the options - I want that gas motor to have duramax-like power. I believe that is as "simple" as slapping on forced induction and injectors. And if I'm doing forced induction, I could even use the 5.3 instead of the 6 liter I think. When I say duramax-like power, that's like 350hp and 600+TQ which doesn't exactly translate to a gas motor i know (yes I know those are old numbers but I'm old). I'm thinking somewhere between 500-600RWHP would be what I'm thinking, I don't have a good frame of reference. This would be a daily driver and a tow rig for my travel trailer, not towing too heavy. And most importantly, I think that much power would be FUN.

Like anything on the internet, there are lots of opinions about how strong the SBE's are. I know I could also upgrade rods and pistons since I'm going to have the rotating assy out anyway, but is it worth it? The crank and block are plenty stout I believe? And then there's the other big question; turbo or roots style blower. I know blowers are better for towing but I believe you end up spending more. I've crunched some very basic numbers for each option but I've been working on **** long enough to know.... you never stay on budget.

 

A Gen3 6.0L is plenty capable. Start with an 05-06 as it will have the better factory rods you are after.

The only way to match the duramax low end torque would be with the 8.1L But then you will be going down a completely different rabbit hole chasing power...

 

The 8.1 is tempting, but it just doesn't have the aftermarket or even factory support that the LS based platforms have. That's the main reason I want to build a gas "duramax". Diesels are such a PITA to work on and I've had a case where my ECM bricked and GM didn't make a replacement for it. Left me stranded for 3 months. With the LS motors, you can find a dozen aftermarket parts for anything that breaks, and I don't see that changing anytime soon.
Edit; I "Grew up" wrenching on Harleys back in the early 2000's. That was my first real reference for torque. I've owned 2 duramaxes; I wouldn't describe them as "low end" torque. The torque doesn't come on until the turbo spools up. Then I rode in my buddy's C6 ZR1 with an aftermarket blower, heads, injectors, etc...1100 HP.... THAT has low end torque.

 

If you plan on towing anything and want low-end torque absolutely do a roots/screw type blower. The upfront cost is more than a turbo, but maintenance is far easier and cheaper and youll be much happier with the power delivery. You are right with the 500-600hp being a good range for FUN. More than that and it starts becoming a lot of work in parts and driving.

 

Easer of maintenance is a big factor. Doing head gaskets or a water pump on my LM7 5.3 is CAKE. Replacing the CP3 fuel pump on my duramax was a nightmare. I can't imagine head gaskets on a duramax. Anyway, the supercharger seems way simpler than a turbo when it comes to additional plumbing and **** hanging all over every side of the engine. And, that instant power... no spool up, you've got ponies RIGHT NOW.

 

Like atomic said, get a tvs1900 kit for whatever you buy and roll on with it. They drive like an oem, make tons of power and are dead solid reliable. I’m certain my blown 408 would walk my tuned duramax even with a load if the trans and driveline could handle the weight.

 

OP, how much are you planning on towing and geographic location? I drive an 06 Suburban LQ4 2500 2wd and really like it. Bone stock. Bought it about 4 years ago with 225k and now at 258k. As far as I know, drivetrain is all original. The previous owner had an F-body/Corvette collection and towed his cars across the country with it. I've only towed around 5k with mine so far.

With 4.10 gears, the LQ4 was rated to tow around 9,600 lbs, and the big block around 12,000 lbs per the owners manual. Pretty good numbers if you ask me. The drawback to towing that high of load is the suburban still has a smaller wheelbase than the trucks, so I think that's the practical limit of them. Otherwise they are great towing, especially with the robust rear leaf spring suspension. The BBC had the 14b 10.5" full float vs 14b 9.5" SF axle for the LQ4 BTW.

I think any Gen III block will handle big power. I've also heard Gen IV blocks are stronger, but had never wondered what's the difference between them. If you are building it, lot's of options like boring, stroking, etc. Obviously a power adder is going to be "mo better." 😁

I'd say if it was an exclusive towing rig and you are towing in the upper bounds of the listed capacities, go BBC; i don't think you'd need to upgrade anything unless you wanted to (check out Lawrence Tolman's 8.1 modified Silverado on YT.) Otherwise the LQ4 will be just fine or if you want to mess around with engine modifications and stuff like that.

I hope this helps.

 

Fancy seein you here!

 

The LQ4 is what I'm imagining I'll end up with. My trailer weighs 7k but at some point I'll get a newer one. The gas motor won't be the primary tow rig. I'm likely going to be buying an LBZ duramax here in a couple weeks. I love duramaxes, the one significant disadvantage is when they break, they normally take me a month to tear off all the garbage hanging on all sides of the motor to get to the problem. And while the Dmax is down, I need another truck to get to work, or take the family to the lake.
I'm glad I'm not the only one whos first though for more power is stroking. No one seems to do that anymore, everyone just says, "Just install a turbo".
Well it's your fault I'm here!

I'll do some looking, I figured if I go that route, I would get a kit from boost district since I think they have the most complete kits, and this would be my first time ever touching a blower. Thanks for the recommendation.

 

Not sure if this is really the right place to ask this, if anyone is still reading this thread. There are 3 CCLB 6.0/4L80's in the area and I'm planning to end up with one of them next week. I'm planning to buy a junkyard LQ4 soon thereafter to do a total rebuild on. I know opinions are worth what you pay for them, and everyone's an expert (hell I know I am. JK).
I've been watching some LQ4 rebuilds on YouTube. I know **** changes over the years and as I mentioned to shakenfake, the best lifters 10 years ago are junk now.
Anyone know of a good source, rebuild thread, video series, whatever, to get a good idea of what's considered "quality components" these days? I figured I'd go with ARP studs for fasteners, and a Melling high volume oil pump. If I do a cam it'll probably be a BTR cam kit with pushrods, springs, etc. For Injectors, if I get them, Injector Dynamics as that's what I've heard is "the going thing" these days. I really don't know these motors or the current market though. Bearings, lifters, gaskets, I should probably even get some education on ARP they may not be the go-to fastener anymore.
Oh yeah... I also need to tally up the numbers as that will probably determine whether I build an upgraded "stock" engine or something a little more wild. The good thing about having a spare motor is I can take my time building it (and buying parts) and just drop it in when ready.