Ready to go LS

[19Suburban69]

I’m getting ready to pull my 454 and go with LS. My truck is a ‘69 C20 suburban with 40 gallon tank and with 2 people crosses scale at 5600 lbs. I can’t make decision between 5.3 w/4L60 and 6.0 w/4L80. It’s set up for towing, but I have no plans on towing. It’s been converted to 1 ton rear end with 3.73. Will there be a problem with smaller engine on this beast?

[LS short box]

I would do the 6.0 and the 4L80E. I don't know your tire size but 4.11 gears would help for towing.
Small cam wouldn't hurt power wise. Depending on the 6.0 consider the newer ones with the better L92 heads.

[REDROCKER652002]

What are you gonna do with the 454? If it is still good, I might be interested for my dad's 56 chevy belaire. Pm me if you are interested in selling.

[19Suburban69]

Redrocker-its sold. I drove it to friends house to tell him what I was thinking and he made a phone call and said it’s sold. It’s still in the truck and I haven’t bought the LS yet! Looking forward to the conversion! Just need to decide which engine to go with.

[mongocanfly]

i have the 6.0 LQ9 in my C30..it tips the scale at just over 6ooolbs..with 4.10s and 31in tires, its a fun ride.. it dynoed 299hp at the rear wheels,and 345 at the engine

[tinydb84]

The smaller engine is plenty but Id go with the 4l80e. We've gone through two of the 4l60e's in my brother's LS swapped Nova and I wouldn't bother doing one in a heavy vehicle.

If you want to be different take a look at the 8.1/4l80e set up. They aren't technically an LS series engine but they have a ton of torque and are pretty modern (aluminum heads/roller cam/efi). You can find them pretty cheap too.

[19Suburban69]

Thanks guys. I think I’ll hold out for the 6.0 w/4L80, put pump in existing 40 gallon, after market harness & computer and use my existing 3 row rad that has twin Derale fans on it. Need to figure manifolds that clear frame without notching. Are fittings available to connect vintage air to GM compressor? I’ve got front/rear air and don’t plan on giving that up! I’m excited in getting this swap going! Pull front clip necessary?

[A1971Blazer]

Originally Posted by 19Suburban69

Thanks guys. I think I’ll hold out for the 6.0 w/4L80, put pump in existing 40 gallon, after market harness & computer and use my existing 3 row rad that has twin Derale fans on it. Need to figure manifolds that clear frame without notching. Are fittings available to connect vintage air to GM compressor? I’ve got front/rear air and don’t plan on giving that up! I’m excited in getting this swap going! Pull front clip necessary?

2010 Camaro manifolds is what I'm using on my 67....I'm not a fan of headers
I removed the ugly heat shields and smoothed them down
They will get jet coated before final assembly
plenty of clearance

[Joemomma1]

Go with what's readily available. Compare the cost of a 5.3 to a 6.0 and determine if the cost is worth the difference in HP. Take the savings and add a cam or something, make more HP than that base 6.0 and still be ahead. Unless you're just wanting to say you have a 6.0 which doesn't impress anyone.

[19Suburban69]

Main reason for 6.0 is truck is pushing 6,000 lbs and I want it be able to tow without concerns. I’m just worried the 5.3 would be boarder line. I could care less about bragging it’s a 6.0.
I like the idea of stock exhaust, I’ve had issues with headers in the past. When they ceramic coat, do they do the inside too?

[mongocanfly]

theres only about 20-30hp diff between early the LM7 5.3 (270-295) and LQ4 6.0 (300-330).. a good tune can get the 5.3 to the 6.0 mark... but the sticker shock will be the cost diff between the 2.. with everybody wanting the bigger engines, they bring a lot more $$..
my 99 Z71 had a 5.3 with 3,73s... pulled some mighty big loads with it,,never had a issue

[JJH Jimmy]

Trailblazer SS manifolds should work but it is all going to depend on the motor mounts you use. I have them on my Jimmy but I built the engine cross member and motor mounts. I got them new on Gmpartsdirect.com and they were like $40.00 each. Not sure if they are still available though?

[BlueJeep]

Originally Posted by 19Suburban69

Main reason for 6.0 is truck is pushing 6,000 lbs and I want it be able to tow without concerns. I’m just worried the 5.3 would be boarder line. I could care less about bragging it’s a 6.0.
I like the idea of stock exhaust, I’ve had issues with headers in the past. When they ceramic coat, do they do the inside too?

My advice would be to decide what you want to do with it, and make the decision from there. I'm about to start the swap on my 86 Suburban and I decided on 5.3/4L60e for gas mileage reasons. The weight isn't a concern, nor is the towing ability. A 2005 Suburban weighs as much or more than your 69, and tows a trailer just fine. I regularly pull my 22' enclosed trailer with my 200k mile 2007 Suburban (with 200k mile 4L60e) and it does just fine.

[19Suburban69]

I’ve bought a 6.0 & 4L80 complete with all accessories, gas pedal w/module, harness and computer for $3k. Has 120k miles on it.
My question now is the motor mounts. I bought LS side mount adjustable plate, but not sure what rubber mount to use. Can I use the big block metal foot mount or do I need small block?

[notsolo]

I think if you have the big block mounts with the clam shell, that's the best option from what I have seen here.

[19Suburban69]

“cam shell?” Not clear on what that is.

[mongocanfly]

Clam.....not cam...just so youll know..
I used the Ebay adapter plates that allow the clam shell to bolt to the LS engine...then the normal sb motor mounts work, and place the rear of the engine in the same location as the small block...
All mounts I used were for a small block..
Heres a clam shell motor mount..
A small block engine mount
And the adapter plates..

[19Suburban69]

Thanks! I didn’t look at my response before sending it. Now I know what clam shell looks like. The mount I removed was just a block of rubber with 3 bolt holes.

[mongocanfly]

I'm not sure what you'll need going from a bb on the truck side ,to the LS...mine had a small block when I did my swap..

[19Suburban69]

I think it’s just a matter of dropping it in and see what fits. I’m looking forward to this!

[kipps]

I recommend the 2010-15 Camaro manifolds over the Trailblazer SS manifolds. The TBSS manifolds kick out a little funny into the frame rail. Not a deal killer, but less than ideal. The Camaro manifolds fit perfectly.

Browse the classifieds on Camaro5.com, and pick up a set of manifolds and downpipes there. Folks ditch them when swapping to longtube headers. Facebook buy-sell groups for gen-5 Camaro owners work well too. You should be able to buy a set for around $100.

[19Suburban69]

Thanks kipps. It helps checking what others have found that works. This is my first experience with LS other than routine maintenance on my Silverado. Engine I’m getting is out of an ‘06 Escalade, but I’m not sure what trans is out of. Hopefully it will be ready for pick up today and I’ll find out. Time to scrub and power wash engine compartment!

[19Suburban69]

Okay, I picked engine/trans. Engine is ‘06 Escalade and 4L80 is ‘05 express van. Got lots of questions. Has block above oil filter (tiny filter!) with lines going forward. Assuming oil cooler? I’m going with stand alone harness (don’t have it yet) but not sure how much of existing harness to disconnect.

[mongocanfly]

If your going aftermarket harness you shouldn't need any of the old harness..
Did you get the gas pedal and controller? Ecm and tcm?
Most likely a oil cooler...got a pic?

[19Suburban69]

I got everything including pedal w/module. Looks like it will need bracket to move it off firewall a few inches. It has complete oil cooler lines, but no cooler. It didn’t have trans cooler lines or dipstick. On removing old harness do I strip all wiring? Like wiring to alternator, starter, spark packs, transmission, etc? I don’t want to pull something and then try and reinstall it. Do new harness instructions cover that? I don’t know squat about LS engines and even less about electrical.