350 vortex or 6.0

[aldang25879]

I will put it this way. My stock L31 350 fullsize conversion van never lost to any of my friends 5.3L trucks or SUVs. With headers and a tune it ran next to a Vortec Max 6.0L extended cab short bed to 80 mph.

400-500 hp and still no torque. As I said all revs and no pull. The kind of cam you would need to get 500 hp out a 5.3L would never run well in a truck and 600 hp is a pipe dream. That would be a 10,000 build or more to make 600 hp from a NA 5.3L. Do you have any experience with a boosted 4.8L? Even with boost they are an absolute dog until 4,000 rpm. A 5.3L with a stock camshaft needs a converter like a Yank 3,600 rpm and deep rear gears to get a heavy truck rolling well. The stock 5.3L I personally setup had a Yank 3,600 converter, a 4.30 gear and a 28" tall drag radial. It ran fairly well but it was not overly impressive. I think it ran 8.70s in a regular cab shortbed from memory. Before the converter and gears it was mid-high 9 second truck in the 1/8 mile. It ended up a 1/2 second quicker than a 1999 Suburban on street tires, with S10 converter, long tubes, volant intake and a tune. Suburban was nearly 600 lbs heavier and ran 9.20s with L31 power. I will choose a Vortec 350 over the smaller LS engines anyday of the week. The LS is marginally stronger in stock form to boost, but not as much as some would lead you to believe. Stock L31 bottom can still handle 700+ hp as reliably as the LS can. Both are a ticking time bomb much over 500 hp on stock internals though. The Gen III just do not hold up in the real world for very long beyond that.

Not to be the “my uncle” guy, but My uncle has a boosted 4.8 on 4.10 gears and drag radials and he whooped a lot of people with it. I can ask but as far as I know he only raced other LS guys not any 350’s. Most OBS guys around here are low riding cruisers. only recently he lost one, he kept up (slightly behind) with a c6 vette until 75-80 mph. It still threw me in the back of the seat though and had me impressed. I agree that he really lost power compared to the vette, when he got stuck in a higher gear and couldn’t get to his higher rpm. But it’s definitely more power than I would be able to handle.

I’m not a genius nor do I claim to be one. I have limited experience. Do you suggest building the top end of a 350 vortec and keeping the bottom end stock? How much power can that produce? What about a supercharger? That would be one Roudy truck. If it’ll whoop my uncles’ then I don’t see why it’s not a valid option.

For context I’ve only had racing experience with 4.8’s and 5.3’s. I have the 5.7 vortec and it’s damn sluggish but, if a rebuild will produce better results, engine swapping suddenly seems unreasonable.

 

[0xDEADBEEF]

Anything can be made fast with enough time and money. Free breathing heads and high rpm are a potent combo in racing.

 

[Erik the Awful]

The OP is asking about a daily driver with a little pep in its step. Once you start recommending slapping a turbo on a "stock" 4.8, you're talking crazy.

A truly stock 350 is a bit of a dog, but at the time it was one of the strongest motors available. The stock 4.8s and 5.3s lack the grunt of a 350, but they're a significant development in engine technology. You can make a lot of upgrades to them to get big horsepower, but you can make a 350 a much more suitable and reliable truck motor for a whole lot less cash.

 

[Scottm]

I'm with L31, stay with the 350. What's really the budget? You would be lucky to spend $3k or less to get the 350 bottom end rebuilt into 383 and the vortec heads freshened up with valves, bronze guides and good springs. Figure another $1k for a roller cam and adjustable roller valvetrain. Then fuel pump, water pump, distributor, fresh torque converter, and might as well replace the alternator and ps pump too. Then there is still the unresolved issues of the intake, injection, ecm, tuning, and exhaust. And of course while the engine is out you should rebuild the suspension and steering. Do you have $8k to spend?

 

[Feral peasant]

I'm with L31, stay with the 350. What's really the budget? You would be lucky to spend $3k or less to get the 350 bottom end rebuilt into 383 and the vortec heads freshened up with valves, bronze guides and good springs. Figure another $1k for a roller cam and adjustable roller valvetrain. Then fuel pump, water pump, distributor, fresh torque converter, and might as well replace the alternator and ps pump too. Then there is still the unresolved issues of the intake, injection, ecm, tuning, and exhaust. And of course while the engine is out you should rebuild the suspension and steering. Do you have $8k to spend?

Not at the moment so that's why it's going for a project plan on going through the whole truck

 

[L31MaxExpress]

I'm with L31, stay with the 350. What's really the budget? You would be lucky to spend $3k or less to get the 350 bottom end rebuilt into 383 and the vortec heads freshened up with valves, bronze guides and good springs. Figure another $1k for a roller cam and adjustable roller valvetrain. Then fuel pump, water pump, distributor, fresh torque converter, and might as well replace the alternator and ps pump too. Then there is still the unresolved issues of the intake, injection, ecm, tuning, and exhaust. And of course while the engine is out you should rebuild the suspension and steering. Do you have $8k to spend?

His 300-400 hp goal can easily be reached with the stock injection, stock cylinder heads, fresh stock 350 short block and a little more camshaft. Intake/Headers/Exhaust and a tune will make 300 crank hp from an otherwise stock L31. Personally I would do the maintenence stuff first, suspension, brakes, fluids, etc. Then the bolt on parts and tune. Then run the stock engine as far as it will go. I have seen some of the L31s go over 500K miles if they do not develop dumb problems like failed intake gaskets that kill them. My buddy has a 1998 K1500 with an upgraded cam that he still uses as a work truck and that bottom end has something like 450K on it. Has a little blowby and some oil leaks now but it still runs strong.

 

[Sean Buick 76]

My vote is find a good running L-96 6.0 and 6 speed auto to swap in

 

[Sean Buick 76]

Turbo everything

 

[L31MaxExpress]

My vote is find a good running L-96 6.0 and 6 speed auto to swap in

That is a $3,500-4,000 pullout here with 200K miles on it. Those 6 speeds are $$$$ to build too. They all have converter issues too that will end up smoking the $$ pump. A quality replacement converter is atleast $750 too. You are at $5,000 before you think about mounting it, plumbing it, wiring it and controlling it. If you want to keep the ac that is another $1,000 by the time it is said and done. A L8T 6.6L from a van or HD truck with a 6L90E is about $4,000-5,000 and those can be found with practically no miles on them. Actually looked at one last year in that price range that had 7,000 miles on it. IF I were going to swap in a newer engine myself it would be an L8T. The L8T pullouts are cheaper than the LY6/L96 6.0L pullouts or the 6.2L pullouts in my area for some reason.

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[Drunkcanuk]

That is a $3,500-4,000 pullout here with 200K miles on it. Those 6 speeds are $$$$ to build too. They all have converter issues too that will end up smoking the $$ pump. A quality replacement converter is atleast $750 too. You are at $5,000 before you think about mounting it, plumbing it, wiring it and controlling it. If you want to keep the ac that is another $1,000 by the time it is said and done. A L8T 6.6L from a van or HD truck with a 6L90E is about $4,000-5,000 and those can be found with practically no miles on them. Actually looked at one last year in that price range that had 7,000 miles on it. IF I were going to swap in a newer engine myself it would be an L8T. The L8T pullouts are cheaper than the LY6/L96 6.0L pullouts or the 6.2L pullouts in my area for some reason.

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In my brief research about the LT motors and swapping, isn't there something wonky with the power steering? Like it doesn't have a pump cuz of electric steering not hydraulic?