Craigslist, you can find 5.3 pullouts with harness for $500, but make sure to pull the valve covers and oil pan and look for sludge before you do, and bring a little magnet to poke around with and see if you get metal flakes from anywhere, meaning bearing trouble.

Don't forget that an LS swap can get expensive, I would stay LT. Just do heads and cam and keep the stock ignition. LE1 kit is only $1100, LE2 is $1600, AI200 is $2200.

 

This is a tech forum. Many of the guys that have been regulars for a while on here try to give the best advice they can drawn from years of experience. When someone comes in and starts talking about converting one of these cars to what is generally an inferior setup for a rather silly reason, it's hard to take it seriously because it's happened before. No offense. One guy a while back actually came in here asking about how to make his LT1 Trans Am run like a diesel and make peak power below 4000rpm.

There's also the highly abstract goal you mentioned of going 200 mph. I think you may get a better response from a lot of the folks on here if you give us some context for these goals, as well as your intended budget and primary use of the car.

Try searching craigslist. I would not pay any more than around $500 for a complete running 5.3 with harness, complete from throttle body to oil pan. As mentioned, pull the valve covers and check for sludge, and stick a magnet up in the oil pan to check for shavings. Also, check the heads for being cracked. Many 5.3s from 2001 to 2006 had a casting flaw in the heads and the heads developed minor cracks and the truck would experience a gradual coolant loss. Avoid any 01 to 06 5.3 with Castek heads, unless you plan on replacing the heads anyway. Do a search, you'll get plenty of results.

As mentioned, the LT to LS swap is time consuming and costs some money, so you may be better off sticking with the LT motor anyway. Again, it all depends on your budget and what you want out of the car, which you've been pretty vague about so far. It's really hard to try to give you advice when you talk about converting to a carb'd gen 1 SBC setup in one sentence, to swapping to a LS-based setup in the next, and then back to potentially improving the existing LT motor in your car.

I, for one, think the idea of swapping to a gen 1 SBC from a LT setup is foolish for quite a few reasons. The exterior dimensions of the motor are the same, so in many ways it won't be any easier to work on in the engine bay of a 4th-gen f-body than a LT motor. With the LT you get a very good fuel injection system, the ability to run much higher compression, set up for a factory roller camshaft, etc. Plus, it's already there.

 

Even an emp apocalypse dooms day vehicle turns into an ls1 swap

 

The EMP business was just a joke. The 200mph, well, that's not impossible. Just very expensive. Plus, I'm not looking for a dragster, or a LeMans car, but rather a car that can "theoretically" make it to 200mph of given adequate space. It can be done. But most likely not with the LT. Not without insanely extensive mods, by then it wouldn't really be an LT.

About going to a carb, it's easier to make big power. Cheaper as well, plus when something breaks, cheaper to repair. That was my reasoning for considering the swap. The LT is better for drivability and reliability, but carbs are much easier to make big power. And i like the idea of having no computers in the car.

And is easier to mad max it out and gave a monkey on top of my carb spitting nitro in it. Duh!

In all seriousness, an LS swap makes the most sense. It's not that bad, i can already get the wiring harness and computer off a 01 SS. Pretty much anything i want off that car.

 

When I drive my injected car to the track and clip off mid 11s at 4200lbs and get high teens for mileage for the day doing it the guys with the carbed stuff are drooling over my car.

If you think a carb is that great go find yourself a early third gen, grow out your mullet and put a 400 with some 202fuelies and a 3/4 racecam in it.

 

A 4th gen with somewhere around 400rwhp, the right gearing and some minor aero mods can probably hit 200mph given enough road. Back in the 1990s Lingenfelter was selling a 383 emissions legal package that advertised 440 flywheel horsepower (this would be around 370-380rwhp) and one of the magazines hit 192mph in a 1995 Firebird Formula with that motor and stock gearing.
In my opinion, a 4th-gen is not particularly safe to drive at sustained speeds above 150 if it's not at least lowered and the wheels, tires and brakes upgraded. In stock form these cars feel a bit light and nervous in the front above 150, particularly when they're not accelerating.

Common misconception. It isn't really any more expensive or difficult at all to make around 500hp in a LT1 than it is in a gen 1 SBC, and it's sometimes cheaper. This is because the LT motors came from the factory with hydraulic roller camshafts, good aluminum heads, the capability to run much higher compression ratios and a relatively lightweight and durable rotating assembly. In the majority of cases, you'll be spending money to add some or all of this to any traditional carbureted small block.

If you have access to a donor car and relatively cheap or free swap parts, then yes the swap does make sense.

 

That's what's making me consider the LS very hard, I've got access to parts for cheap from a coworkers donor car. He took the motor and trans for a mustang swap. He got an after market harness, and has given me first dibs on any and all parts.

And the v third Gens, those are my favorites. Was trying to find one before i got this one, but most were to far gone or needed more work to get on the road.

My 96 TA only needed tires and tune up stuff. Everything still good and tight at 102k miles. All the 3rd gens were worn out, and the ones that weren't were to high in price.

On my 82, i assume i was north of 400hp. Never dynoed, but also would stomp brand new cars in 2000-2003. It was straight carb, big carb, fat cam, giant intake. All with stock rotating assembly except the rockers and valves. Ended twisting the crank so bad it wouldn't turn even by force. Learned a valuable lesson then.

Upgrade your bottom end BEFORE putting heavy horses on top.

From my searches, it seems everything is more expensive than carbs, plus you gotta get everything tuned, which is much more involved than a carb setup. Can't do much by ear with the LT1. I can't atleast.

But the LSx stuff is wallet breaking mostly. Not too bad, just means i gotta save for a few weeks longer between projects.

I've been thinking hard about finding a 3rd Gen project, and swapping my parts to that.

Really what my situation is right now is this, I'm 31 and believe I've finally gotten bored with video games. I keep telling myself "maybe the next one will be better", but they all suck and have become more boring than regular tv. So I've been contemplating selling my gaming stuff and investing into my garage. Get some big boy toys instead.

 

^^^ Get a stripper wife

These motors are a lot more stout than the old SBCs. Look up xrambbc on here.

Stock longblock except cam/single plane
Rebuilt with wider bearing clearances/ring gaps
SAE numbers are 784rwhp/820tq @ 22 psi
GT4202
water/air intercooler
220 230 .544 .544 114 comp cam
dual springs
105# injectors
114 octane
Spun to 5800 RPM


Biggest weaknesses are things like rods/rod bolts/main caps. Keep the RPMs low and you won't have to worry about the main caps walking/fracturing or PM rods snapping/big ends distorting/bolts shearing. RPM is a lot harder on a motor than excess power, especially because the LT1 pistons are taller and 100g heavier than the LS family.

If you have access to the LS1 kmember, harness, and a somewhat cheap and low mileage motor then go for it. But the LT1 is up to the task as well if you understand its limitations.

 

Then perhaps you should consider that. You'll need a motor and transmission, since the transmission from your LT car won't bolt up.

If your 102k mile LT motor is in good shape, do a heads/cam swap. Such can put you over 400rwhp for a whole lot less money than building a whole new engine. 102k miles is not a big deal on one of these cars if they've been well-maintained. Look around this section, you'll find many 100k+ mile cars running around with H/C/I making over 400rwhp and running 11s or quicker, and some are even sprayed on top of that. The LT motors' durability is well known.

400hp, whether measured at the flywheel or rear wheels, is not "heavy horses" in the LT or LS world.
If you've "twisted" or broken a crank at that power level even in an old-school SBC it's most likely due to bad machine work, a bad cast Chinese crank, neglect or abuse. Most any factory crank can handle at least 500hp, and often a lot more.

Make sure you're comparing apples to apples. Yes old-school flat-tappet stuff for traditional SBCs is cheaper. You'll also make a lot less power. For instance, my LT car with just bolt-ons and a heads/cam upgrade on a 100k+ mile factory motor will handily slam the door on almost any old flat-tappet 9.5:1 carbureted small block put together with parts from a Summit catalog.
Once you compare full roller stuff you'll see the prices slide right in line if not exceed what LT stuff costs. One advantage of the LT is there's no need to mess with the intake manifold until you're making north of 450rwhp.

Not really, if you know what you're doing. Long block assemblies in good running condition for 5.3 truck motors are everywhere in junk yards for around $500. Parts for LS motors, new and used, are literally EVERYWHERE. If I wanted to, I could put together a 600hp turbo 5.3 LS setup for about $3000 and a few afternoons worth of work. That's why boosted 5.3s are so popular right now.

Seems like you've got a lot more research to do.

 

I definitely need more research, no argument there.

I'm not looking for drag racing. Ultimate goal is auto cross, but I want to go fast. Real fast. End goal is to be able to safely go 175mph+.

I found a couple of 5.3s at a local junkyard. Forgot the prices, but we're reasonable. Under 800 for sure. I don't need anything really running, as I'm gonna rebuild it completely. I've found blocks for cheap, but wanna start with a complete motor to learn more.

Not doing much for the holiday weekend. Maybe the wife will take extra baby duty and let me research more.

 

Put a SS hood, wing, and rims on it and you'll be alright 😂

 

Lt1 200mph madmaxmobile would be beast. Would it be safe to run AI heads since they were ported on a 5 axis robot? Or would hand portedb heads be better in an EMP apocalypse? Jus asking?

 

Funny you should say that. It's been quite a few years since I dared drive mine that fast.
I have driven a LS1 car with SS hood, wing and wheels on it over 160 mph in the past and it felt light in the front and a bit jittery at anything over 150 too. Not horrible, but these cars definitely don't feel nailed down at those speeds unless they are at least lowered a couple inches.
For some reason, the nervousness seems more pronounced when maintaining a constant speed of 150+ than when actually accelerating.
I have also driven one lowered on sportlines at those speeds and it felt much better all-round. If I were to have one of these cars that I planned to drive at those speeds with any regularity, at the very least I'd want a C5 brake upgrade with stainless steel lines and DOT5 fluid, a roll bar and a set of Strano springs and quality shocks. I'd also want the chassis tied together with subframe connectors, a good set of 18" wheels and tires and some basic aero tweaks done to enhance stability.