Budget 5.3 Swap

[chiggins]

MAIN POINT: What have you guys done for a bare bones, budget 5.3 Vortec/LS swap into your trucks?


THE STORY: While I continue to dig and do research for myself, I figured I would throw up a post to hopefully get some answers.

I currently have a '68 with a frankensteined 307 with dangerously low oil pressure, a weak saginaw 3 speed, and I believe a 3.07 rear that a PO slapped in to get a few extra mph's. The truck is a dog and just not exciting by any means of the word. Needless to say I'm looking to spice it up.

I have an L31 Vortec 350 sitting that I've already put together a pretty extensive parts list together for. I'm looking to build a rather healthy and reliable 400 HP, low-end torque little monster out of, but I'm already looking at close to $2k worth of parts plus assorted machine shop costs. While to some guys that may just be pennies, but I'm a college student that serves on weekends. When I say budget I mean BUDGET.

On the other hand, I have a complete (but disassembled) 5.3 motor out of an '02 tahoe that I picked up a couple of years ago for dirt cheap. That includes intake and fuel rails, but I don't think I have the ECM. It's been a while and I haven't been back home to take stock of what I have. I'd like to cam swap it and build as close to 400 hp as I can NA. If I can swap a 400 hp ls into the truck for somewhere between 2,000 and 3,000, I'll just spend the extra little bit and go that route instead of the 350.

Other details: I picked up an NV3500 to put behind either engine. It actually came with the flywheel set up for the LS so thats a plus. I intend on installing probably a 3.73 locker in the rear, but if you have other gear size recommendations let me know. It has a relocated Boyd tank in the rear with provisions for a drop-in fuel pump, also a plus.


So the big question is: what have you guys done for cheap LS swaps?

What did you do for Fuel/Air delivery? Carb? Stock intake and injectors? aftermarket EFI kit?

What about internals? Cam? LS6 springs? LS3 heads? All aftermarket?

And the list goes on. I'm hoping to make this into a definitive guide sort of thread that myself and others can use for our own projects. So please give as much detailed information as possible.

Cheers!

[chiggins]

Additional Questions:

What did you use for electric fans and radiator?

What did you use for accessories?

What about throttle? Did you pull the drive by wire out of a newer truck?

What about power steering?

What about gauges? Did you splurge and go Dakota Digital? Or slapped something together?

I know that this is a much more involved process than just building the 350 and throwing it in. But if I can be shown that it can be a simple swap for a novice like myself, and for not that much more money, I would love to see what was done.

[MDPotter]

I'll answer as much as I can here without getting too deep in the weeds.

Cam and springs will get you the biggest gain, I would anticipate 50 HP. That engine probably makes 295 in stock form, and even with cold air intake and free flowing exhaust, you'll be short at least 40 without other mods like an LS3 intake or having your heads milled to bump compression.

A lot of guys have been able to adapt the stock behind the seat tank to work by adding a return line and an inline fuel pump and filter. I went with a Tanks Inc universal tank and in-tank pump, but that's $650 and not nearly as convenient as a Boyds tank.

Keep the accessory drive if it came with it, otherwise just scrounge up parts from the junkyard and from Rock Auto.

You'll need motor mounts as well. I used the stock perches, but bought new rubber mounts with aluminum adapter plates.

You might have to buy or fab a transmission crossmember.

A lot of guys make the stock gauges work with the LS too. I spent some money and went with New Vintage gauges, but not necessary.

If it's an 02, it's probably drive by cable. Easy enough to source a cable throttle body from the junkyard and hook it up to your stock pedal.

You can buy PCM's for pretty cheap that have already been programmed to get rid of VATS and other LS-swap required changes. If you're putting on power adders, you'll need a tune though. I don't know how familiar you are with tuning, but you can buy HPTuners and do it yourself for not much more than you would spend on a dyno tune or a mail-order tune.

I spent $200 on a radiator with dual fans and trans cooler on eBay and it works just fine. The fans are cheap so they will probably go out eventually, but no big deal to change them out.

I'm running stock intake and injectors, but they're pretty well maxed out with my moderate cam.

Power steering - I'm using a reman LS pump. I had hoses custom made to connect to the steering gear and booster.

There are plenty of builds on here with LS swaps (mine included), so my advice to you is to start reading through those builds and researching products because there is such a huge aftermarket for LS swaps.

Be prepared to spend some money though. It can nickel and dime you when you start replacing engine parts (spark plugs, wires, water pump, belt, starter, etc.) and there are a lot of little fittings, electrical items, etc. to make it all work together.

[mongocanfly]

Im not sure what your budget is,,,but you've blown a bunch on your wish list..
With the LS,
obviously you'll need to rebuild since its torn down.$$.
I run stock accessories..if you dont have those that's more $$
ECM...$$
Wiring...$$
Fuel system..$$
Trans to engine adapter for nv3500..$$
Rear gear choice will depend on trans and tire sizes to determine final gear ratio..
Rear end..$$
You can run power steering off the LS pump..
You can use stock gauges with metric to standard adapters..
I used stock radiator and dual electric fans..
You may need a convertor box from pulse to cable drive for the speedo..$$
You'll need a tuner to unlock the ecm..
And a wiring harness..$$
Is the 5.3 a dbw or dbc?...dbc is simplest and cheaper

[mongocanfly]

Just keep in mind , when you up the hp it affects all the downstream components..they need upgraded to match power output..
I think you mentioned a carb for LS....that's not cheap

[LS short box]

Just fyi a LS3 intake will not work on a 02 5.3. The cylinder head ports are rectangle on the LS3 intake. You could use a LS6 intake but if you are on a tight budget I would just stick with the stock intake and injectors. As said above a cam, valve springs and push rods along with a good tune will really wake up that 5.3.

[kipps]

Check out this thread from a month ago. Particularly note Gregski's response in that thread.

[LS short box]

Again just FYI. The LS3 or L92 heads will work on a 6.0 block. But you will need convert to either LS3 Camaro or LS3 Corvette intake or a 6.2 manifold. Again check with the guys on LS1 tech to see if what combos work the best.

[3767]

First off....guard on the weekends...thank u for your service.
Either way u go u will blow that 2k to 3k budget. Forget the motor for just a second and let's look at the total of what u have. The rear end will need an upgrade. U will need a kit which will give u the seals,r&p crush sleeve and bearings. U can't really take any advantage of that tranny till u do. That 3:07 gear is somewhat of an over drive n it's self. Neither motor is gonna do what u want with that gear back there. For what u want vs the money u have the 350 makes more sense to me. No computer needed,most of what u will need can b found at the local pats store or online by a number of vendors. The machine work needed is mostly the same so I would b surprised at a real difference n cost. The 5.3 can make more power but it will cost more due to all the electronices involved. U can carb it which will help balance the difference. Both engines will want the same size so no winner on either.the 5.3 will need the edelbrock carb set up. U can find a used 1 on eBay,or Facebook mkt place. Which ever 1 u pick, sell the other 1 off to help with the funds of the keeper. The ls is nice and making 400 is easy with it but I'm looking at all the other things on that wish list that u will need to get that "torque moster" u crave.

[kipps]

My recommendation -- Forget the 400-hp figure, and skip the rear-end swap for now. Use your stock 5.3 cam, spend a couple hundred on a complete gasket kit for the engine, and assemble it as is. Bolt it to the nv3500, and stick it in the truck. Go with a stock ECM, and just do a mail-order delete on the VATS, emissions, and auto trans. This should get you on the road for the cheapest possible.

400-hp would be nice, but a stock 5.3 at slightly over 300, is far better than what you currently have.

When you find a better rear-end, swap that as a separate project.

Down the road a bit, swap the cam, install a turbo, learn hptuners, and do your own tuning.

I plugged your numbers(guessed on some of it) into a gear ratio calculator. It looks like the nv3500 should function well enough with a 3.07 rear and 29" tires. Meaning, the shift points aren't wildly out of whack, etc. You may still want to swap the rear end at some point, but I would definitely leave that till later, when you find a good deal, and the budget is a little less strained.

[verdell]

Originally Posted by kipps

My recommendation -- Forget the 400-hp figure, and skip the rear-end swap for now. Use your stock 5.3 cam, spend a couple hundred on a complete gasket kit for the engine, and assemble it as is. Bolt it to the nv3500, and stick it in the truck. Go with a stock ECM, and just do a mail-order delete on the VATS, emissions, and auto trans. This should get you on the road for the cheapest possible.

400-hp would be nice, but a stock 5.3 at slightly over 300, is far better than what you currently have.

When you find a better rear-end, swap that as a separate project.

Down the road a bit, swap the cam, install a turbo, learn hptuners, and do your own tuning.

I plugged your numbers(guessed on some of it) into a gear ratio calculator. It looks like the nv3500 should function well enough with a 3.07 rear and 29" tires. Meaning, the shift points aren't wildly out of whack, etc. You may still want to swap the rear end at some point, but I would definitely leave that till later, when you find a good deal, and the budget is a little less strained.

I would go this route as well. Motor mounts can be had for around $69.00, crossmember isn't that bad, do a search for camaro manifolds, use the truck intake/injectors/fuel rails, drive by cable is simple/inexpensive, etc. As far as rear end gear ratio, a shorter tire will help for the time being as well. Use your radiator.