How much power can I make from a 5.3l LS with these limitations?

Well aside from the fact that many people here don't believe you can increase power through efficiency, what did we learn here today?

To sum up, accomplishing my goals means I should:

1. Get a full exhaust system including long tube headers
2. Use a custom ground cam.
3. Polish, but maybe not port the heads
4. Slightly stiffer valve springs
4. Get a tune
5. Aluminum driveshaft
6. ??? What else
 
I haven't driven a TBI 350, but I had a '96 C1500 with a 350 (Vortec) and I loved that motor.

I've driven an '03 Silverado 5.3L and '05 Tahoe 5.3L and they were gutless. My 350 would have flown past them.
They felt that way because of torque management. It was not faster. I have a 97 Vortec 350 sitting in the driveway. My 04 5.3 1/2 ton was light years better. Once you get past 3000 RPM it is totally different story.
 
Like Cline said. Get yourself a 6.0, if you really want a 5.3. A mild cam and set of heads will wake it up. My LS1 Trans Am has had heads and cam for over 55,000 miles, no issues. The Caprice is coming up on 45,000 daily driven miles with a mild BTR stage 1 cam for LS2/LS3. If the install and tune are done correctly you won't hurt reliability at all. Any transmission you chose will be fine with certain upgrades. Just depends on what you are looking to do.
You could look into an already built wiring harness. That helps. I did a LS1 swap on a 70 Corvette with a buddy and he picked up a custom harness. It was pricey at 600 bucks but well worth.
 
Nice swap idea. Problem with these swaps is.....it's never just a swap. You'll want more. After the swap it's only going to be 1 or 2 months before that open space called a truck bed gets occupied by a certain bottle of compressed magical unicorn juice or a set of spinning boys.

Deny it all you want, I bet you looked into it already. Might as well do it right, do it once. You don't need anything magical on a ls. While it's out....might as well throw new gaskets in it and do a full bearing check......AAAAAAAND throw some ring gap at it, a 459-11 cam, springs.

Just don't lie to yourself, you know **** well you going to spray it.....or worse.
 
And for those saying to go old school sbc, you're nuts. The LS is a way better engine for power and economy . The worse LS head can support 450hp. Show me anything factory sbc that can make 1200hp with nothing more than ring gap, cam, spring, boost....that was done on a 4.8 LS.

OP, the LT motors are even better. Convert to Port injection, cam, springs, even a 5.3 Gen 4 can make North of 500hp....easy.

LS/LT engines are probably one of the best engines made for out of the box for power production, cost, retrofit, etc.

AS A FORD GUY, it hurt so much typing that. Just admitting it caused anxiety....
 
Nice swap idea. Problem with these swaps is.....it's never just a swap. You'll want more. After the swap it's only going to be 1 or 2 months before that open space called a truck bed gets occupied by a certain bottle of compressed magical unicorn juice or a set of spinning boys.

Deny it all you want, I bet you looked into it already. Might as well do it right, do it once. You don't need anything magical on a ls. While it's out....might as well throw new gaskets in it and do a full bearing check......AAAAAAAND throw some ring gap at it, a 459-11 cam, springs.

Just don't lie to yourself, you know **** well you going to spray it.....or worse.

I totally understand what you're saying and I've done it before. But... not this time. This time I'm building a classy old street squarebody that I want to last. And once it's built, I want to work on it as little as possible. That's why I want an LS, their reliability. This is because I've got other cars I'll be working on, and I need to get the old squarebody over with. Spraying it isn't the way to reliability. This truck is all about being leisurely, not really speed. That's part of the reason I wanted to increase the gas mileage, rather than decrease it. It's nicer not to have to stop at the gas station as frequently. So if I take it on any tours, it's nice to have to stop what you're doing and go fill up. Every bit of mpg pushes that out just a little bit further, and I'll take it.

So this was never going to make big power, but I did want to squeeze out every last drop you can get without hurting mpg.
 
I totally understand what you're saying and I've done it before. But... not this time. This time I'm building a classy old street squarebody that I want to last. And once it's built, I want to work on it as little as possible. That's why I want an LS, their reliability. This is because I've got other cars I'll be working on, and I need to get the old squarebody over with. Spraying it isn't the way to reliability. This truck is all about being leisurely, not really speed. That's part of the reason I wanted to increase the gas mileage, rather than decrease it. It's nicer not to have to stop at the gas station as frequently. So if I take it on any tours, it's nice to have to stop what you're doing and go fill up. Every bit of mpg pushes that out just a little bit further, and I'll take it.

So this was never going to make big power, but I did want to squeeze out every last drop you can get without hurting mpg.
Then you want a 4.8 or 5.3 with as many gears as possible and keep it stock. I have 3 modified LS based cars. (LS1 Trans Am, L77 Caprice and a L96 Truck) modifications are not going to help your MPG with a LS (in my experience). The truck has a tune, which woke it up and made it shift proper, but MPG remained the same empty or towing. 15ish empty, 8-10 towing. The Trans Am has a ton of mods, (heads, cam, intake, exhaust, ford 9 inch, etc) maybe 17 around town, 23 on the highway in 6th gear going 60-65. The Caprice lifetime average right now with Cam, axle back, CAI is 16 mpg.
 
I totally understand what you're saying and I've done it before. But... not this time. This time I'm building a classy old street squarebody that I want to last. And once it's built, I want to work on it as little as possible. That's why I want an LS, their reliability. This is because I've got other cars I'll be working on, and I need to get the old squarebody over with. Spraying it isn't the way to reliability. This truck is all about being leisurely, not really speed. That's part of the reason I wanted to increase the gas mileage, rather than decrease it. It's nicer not to have to stop at the gas station as frequently. So if I take it on any tours, it's nice to have to stop what you're doing and go fill up. Every bit of mpg pushes that out just a little bit further, and I'll take it.

So this was never going to make big power, but I did want to squeeze out every last drop you can get without hurting mpg.
If you want both power and mileage, that's like having your cake and eating it too. Rarely happens.

IMHO, transmission and rear gear is more important in this case. Personally, I'd go with a 6.x and a long runner manifold to maximize torque and get that big truck moving. Keeping the variable cam timing will help that.
 
If you want both power and mileage, that's like having your cake and eating it too. Rarely happens.

IMHO, transmission and rear gear is more important in this case. Personally, I'd go with a 6.x and a long runner manifold to maximize torque and get that big truck moving. Keeping the variable cam timing will help that.

I've heard of people who increased power and fuel mileage. They increase efficiency, say by adding a full exhaust system including headers. I'm just looking for all the little tips and tricks like that for the 5.3L, aside from the obvious well known ones. If there are any, maybe there's not.
 
Guy wants a simple swap for his tired truck and everyone is building him something ridiculous.

I would get a stock aluminum 5.3 and put long tube headers on. That would be the only mod.
 
If you want both power and mileage, that's like having your cake and eating it too. Rarely happens.

IMHO, transmission and rear gear is more important in this case. Personally, I'd go with a 6.x and a long runner manifold to maximize torque and get that big truck moving. Keeping the variable cam timing will help that.
Like a L96 out of 3/4 ton and up gasser? Plenty of those around and they are 360/380 stock.
 
You will end up throwing $100.00 dollars bills after you run out of the $20.00 bills. The best bet would see if some king of GM crate engine would bolt in again it will cost lots of dollars and head aches.
 
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Hi all. I'm looking to replace the dead 350 in my old 87 Silverado. Needs new piston rings. I want to use a 5.3L LS engine from a newer truck, but I figured why not add a little spice to it first. However, there are some limitations I want to abide by. They are:

1. Can't harm the factory fuel mileage very much.

2. Can't harm engine longevity. I want the engine to last 200k miles or whatever the 5.3L is typically known for.

3. Can't harm the factory road manners. I want the factory idle, so no rough cam. No obnoxious racket or bad smells.

Even given those restrictions, I believe there is still room for improvement on the 5.3L LS engine. We just have to get into the details. For example, I don't want a loud exhaust, but that can be mitigated by using flowmaster hushpower mufflers. And I can't use a big cam, but there is room for a slightly larger cam that won't affect the idle any.

But what else? What all can I do to improve power, while not spraying much more fuel? Should I do a medium overbore on the cylinders? Polish the cylinder heads, but no porting?

What are all the specifics of such a build? Thank you

Swap some -243 heads onto it. Throw in a mild cam. Get rid of those ****ty flowmasters. It's not a mustang. Get a proper tune. Should have you at around 320-350whp depending on the cam, and completely streetable/stealth. If you want to go wilder, some aftermarket heads and a bit more aggressive cam. Back when I was driving an LS1 car, I raced a g uy who had a 5.3L in his F-body because he blew the LS1 up. Had 241 or 243 heads, IIRC, and otherwise stock internals for the 5.3. yeah I won, but it wasn't like I murdered it. I'd say he was putting down 250-270whp. Died on the top end mainly.

A stock LS1 engine, swap the cam while it's out, sounds a whole lot smarter and cheaper to me...

LS cars used to be my passion :)
 
Hi all. I'm looking to replace the dead 350 in my old 87 Silverado. Needs new piston rings. I want to use a 5.3L LS engine from a newer truck, but I figured why not add a little spice to it first. However, there are some limitations I want to abide by. They are:

1. Can't harm the factory fuel mileage very much.

2. Can't harm engine longevity. I want the engine to last 200k miles or whatever the 5.3L is typically known for.

3. Can't harm the factory road manners. I want the factory idle, so no rough cam. No obnoxious racket or bad smells.

This is pretty easy

What you're describing is camshaft with minimal overlap and with lobe profiles that are easy on the valvetrain.

I'd suggest:
Intake lobe - 208-212 degree (@.050)
Exhaust lobe - 214-218 degree range (@.050)

LSA above 110

For shelf cams I'd suggest:
Comp Cams XR265HR (212/218 112/116 .522/.529) or BTR Stage 2 Truck Cam V2 - BTR31218110 (212/218 111/111 .553"/.553")

Valve events for the Comp XR265HR:
Intake Opens BTDC: -6
Intake Closes ABDC: 38
Exhaust Opens BBDC: 45
Exhaust Closes ATDC: -7
Overlap: -13
Lobe Separation Angle (cam degrees): 114

Valve events for BTR Stage 2 Truck Cam:
Intake Opens BTDC: -5
Intake Closes ABDC: 37
Exhaust Opens BBDC: 40
Exhaust Closes ATDC: -2
Overlap: -7
Lobe Separation Angle (cam degrees): 111

Versus the BTR cam the Comp will have a slightly softer low end, a slightly stronger top end and but less idle chop
The BTR cam will provide sub-2500 rpm HP/Torque on par with the stock truck cam but will run away after

Both cams provide relatively tame idle characteristics, excellent low-end torque and huge mid-range/top end improvement (40+ HP at peak) versus the stock cam.

You could also install the BTR cam on a 112 or 113 intake centerline to tame the idle even more for a slight trade-off in sub-2500 HP/TQ.

Pair up with a TBSS intake, hardened pushrod/spring kit, and a quiet yet high flow exhaust and have fun.




 
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