Shorter back story: The car is a 1984 Camaro Z28 that had the 305 HO and has the T5. I blew the engine, pulled and sold it, but still have the T5.
I have a 2000 Silverado with a 5.3 that we are pulling and replacing with a 6.0. We upgraded the cam, springs, seal, gaskets, rings, and bearings, which ran about $1400. Then headers added a couple hundred, but wiring and accessories were already present, and the intake is already there as well. And tbh, I really enjoyed tearing down and rebuilding the 6.0, and would not mind doing this again.

So now I have a 5.3. But if I spend another $1400 for the same parts as above, but also need an oil pan, motor mounts, wiring, fuel pump, water pump, accessory bracket, headers, and have no chance for A/C, that will add another $1500-$2000.

On FB marketplace there is a 93 LT1 engine from a Corvette, 4 bolt main, including starter, standalone engine harness, fuse panel, pre-programmed ECU. VATS, downstream O2,, EGR, and all unnecessary sensor data has been removed. Comes with a Camaro harmonic balancer, accessory bracket, PS pump, alternator, and AC delete pulley. Also has Flowtech shorty headers. He's asking $1800 for the engine and some extra cash for the headers.

How difficult would putting the LT1 in? This is not anything I considered, as my original plan was using the 5.3 that I have vs just replacing the 305 with a 305 SBC.
So I have not researched this swap at all, and have no idea what all would be involved.

 

Although the LT1 is more bolt in friendly and can basically use everything mechanical that supported the 305 I would go 5.3. However, if you don't want to deal with exhaust, front accessories, etc, than I would look at a traditional small block swap. There is nothing special about the LT1 other than it has a funky coolant system and the ignition system is a sub-optimal design.

Before you do anything, spend some time reading the stickies at the top of the LS/LT swap forum. You'll start to see what you need to consider and can judge if its something you want to tackle or not. Plus, reading is free, and you're money will be better spent with some knowledge in your dome.

Practicality of swap. Headaches vs benefits.

5.3 > LT1
SBC > LT1

 

5.3L = Gen III/ Gen IV SBC.

Gen III/ Gen IV SBC > Gen I LT1 SBC.
Gen III/ Gen IV SBC > Gen II LT-1 SBC.
And most importantly...
Gen III/ Gen IV SBC > Gen V LT1 SBC.

 

Last silly question for a bit. And TBH, I always have a hard time making decisions, so thank you for your patience with me!
93 Buick Roadmaster engine is not an LT1 (from what I understand). One is on FB for $600.
My goal is still about 300hp to the wheels. I still have the intake and carb from the 305. Could I not take this 93, use the carb and intake, mild cam, new springs, rings, gaskets, and get about 300 out of it? This would be easier technically than wiring, mounts, fuel pump, etc that would be needed for the LS that will eventually be out of my truck. Still gonna use the T5 that I have

 

I agree the LT1 is not a good option due to the weird electronics. The 5.3 is a good swap and can be made to work w a t5 but will take a little work/$ to bolt up to everything. The road master engine is a tbi 350. That is easy enough to get to get 350 hp w a cam, heads and intake. All the stuff you had on the 305 will fit and you'll be up and running quickly. The 5.3 should be really easy to get more hp out of but the swap is slightly more challenging. I assume you're using a carb with either engine. If going efi, theres a bunch more to consider.

 

If we continue with the LS, we would likely do fuel injection but then would need an intake, fuel pump, re-routed fuel lines, so certainly more work. While I know better fuel economy, easier tuning, easier startup with LS. But I have the intake and carb from the 305, and just like the idea of keeping things old school, so am perfectly fine staying carbed. My son disagrees! 😄

I'm sure if indig deeper I could find it, but are there heads for the 350 to really look for or to avoid?

 

Kinda, but not really. All of them have limits, some more than others. The 083 TBI heads (350 TBI) are pretty poor but can be improved with some port work. A set of L98 heads (350 TPI) is probably your best bet assuming your intake is not for Vortec heads. To be honest, that's the route I'd go. L31 vortec heads, and buy a new intake. Another option is new castings all together. Summit has their own SBC heads now which perform pretty well. You'd probably spend less on a new set than buying and refurbing a used set. Or be bold and try the Veevor heads.........JK. They require extra work to undo the chineseum in them,

 

if it were me, and i was looking for engine swap ideas, i surely would not chose 45 year old SBC technology.
Ls all the way.
Everything about the LS is better then the SBC in nearly every way.

you can have 400 hp with a cam swap, and still get 20+ MPGs with the ac on
SBC wont do that.

Zero wrong with a SBC, but again old tech. The only thing you have to modify is the fuel system, and its pretty easy to do

 

A set of l98 heads would work awesome w a nice little cam. It would make for a nice torquey engine. If you used those heads w a zz4 cam you'd be in the 350 hp/400tq range. Not a high flowing/revving setup but fun/stable and reasonable in price. Thats probably the ball park you'd be in w some simple mods on that 5.3 w less work!


the whole LS thing is cool but will be more money in. I cant see doing an LS w a carb. You need a whole new fuel system so new fuel lines/sender and in tank pump. So why not go for efi!

i have an 82 that has a efi 350 w a supercharger. It initally had the same drivetrain as your car. I put a zz4 in it w the t5 years 25 ago. It was a blast. Then I wanted more and more. Think about your end goal. You want a 350 hp fun car? You want 550hp? You build up a gnarly LS, you're gonna need a better trans and rear.

how deep do you wanna get!?!

i will say, my 350hp and then 430hp setup and then 560hp setup all were the same speed on the road in a way. You really cant easily open up a car that fast on most public roads. My car is fast as hell and on occasion i get to use the power, but its not often. So i get to say i have X amount of HP and have cool guy blower whine. Do i get to use it all, not much at all. But its all relative. I have a friend w a 900hp street nova and another friend w a street 2000hp mustang.

so how deep do you wanna get?

 

LS all the way as said. SBC is old. LT1 is technically SBC when you get down to it. Same limitations stemming from the block. Slightly better heads, arguably better intake overall, but not better than a SuperRam.

LS 5.3 will make more power everywhere. Newer computer, better tuning support. Will tolerate larger cams while retaining drivability because of that better computer. Much MUCH better head design, way more efficient. Better intakes. Way more mod potential. Block will handle much more power on stock internals...etc.

LS kicks the crap out of SBC and for good reason. GM took everything they learned over 50 years and put it into a clean sheet design on the LS.

And in today's world, the LS is easily supported as a swap in the aftermarket with little to no drawbacks.

Swap in a 5.3 now. Easy to move to a 6.2 LS3 later. Want boost? Can put a magna style supercharger right on top and fit under the OEM hood.

 

i know i 'preach' the Ls swap all the time. Yes it can cost more due to things needed, but, there is a reason it is the number 1 engine swapped in todays world.

dont get me wrong, i love old iron, i have a 383 and a 496, but ill tell you from experience, the Ls just runs better.
But it all comes down to what the person paying for it can do or needs help doing.

The SBC might be the easiest way to go for him.

 

I would never pay even parts to rebuild a SBC. The 5.3 is already there in the garage. If it's running just get what needs to be got for the swap and drop it in. Double the power.

 

I've read the sticky a million times, read the RB groups, etc. on the LS swap, and I have the ability and tools to rebuild the engine. What I have not found in my research is more about the "little things" since I am keeping with the T5. Everything talks about going to a T56 or using the 4L60E. Can I keep the same crossmember and driveshaft with the LS? Will I need to move the pedals at all? I'm not going with a/c since I don't want to buy a tubular k-member and can't notch the stock one, but do I need to notch/bend/beat it for room for the oil pan? How hard is it to get proper engine mounts? I can use an inline electric fuel pump rather than replacing the entire tank, but will need to re-route the fuel lines a little since they come into mid-passenger side on the 305 but top driver side on the LS. Not to mention needing a standalone harness (I have the harness from the 6.0, but it was cut at the level of the computer).
These are the things that make me cautious about the swap. I don't have the ability or the courage to fabricate things. If I can't buy it, I likely can't do it.
Am I over-reacting? Likely. Will I look back and feel silly? Likely. Unless the car turns into a giant paperweight in my shop...

 

Getting the ls hooked up to the t5 at the proper 17deg angle may be tough. Look at three pedals .com also look at quick time bellhousings. You need an adaptor bellhousing or an adaptor plate. Also, most older truck ls engines aren't drilled for a pilot bearing. There are jigs to help w that but its a deal. Most LS mounts place it in the same spot as a regular sbc. I totally disagree w the comment about not putting money into a SBC. If its the path or least resistance its a good move.

Moving fuel lines is easy. Inline pumps run hotter and burn out much faster. The in tank units are cooled by the fuel.

 

GM took "Most of Everything" that they learned from over all that time for sure!
Definitely not a "clean sheet design" though.

Many of the improvements found in the Gen III/ Gen IV Small Block Chevy can been seen well before it, earlier on in the Buick FWD 3800 V6 Engines and some small improvements in the Vortec Gen I Small Block Chevy V8 and V6.
If not for the advancements made for the Buick V6 Engines, the Gen III/ Gen IV Small Block Chevy would have been very different engines.

 

You could not give me a gutless 5.3L. SBC is still alive and well today. There are excellent budget heads available now that allow a Gen1 to run circles around anything a 5.3L can get and the SBC will equal the LS in fuel mileage all day long. The SBC will make more torque in the normal daily driving RPMs which is more fun to me than reving a gutless wonder to 6,000+ RPM just to merge on to the highway. Cube for cube you can get just as much HP and more torque from a Gen1 for less money.

 

Are you referring to Vortec heads or others? The intake (Edelbrock Performer) is not Vortec, so doing standard heads would be preferable.

I did find out today that Accurate Engines can build a 390 horsepower 350 delivered for around $3,000. Comes with a 3 year/100,000 mile warranty. Kinda hard to beat that.

 

I am talking aftermarket heads like Dragon Slayer, Promax Project X, AFR Enforcer 2nd generation, and several others.

 

Well when going to Aftermarket Cylinder Heads there is potential to make 700 - 800 HP Normally Aspirated depending on Displacement and RPM...
And the sky is the limit with Forced Induction and/ or Power-Adders!

 

I don't want to go anywhere near that. This is a street only, nice day driving, kind of car. Dyno tested 195hp/220lbft on previous 305, so my goal was 300hp at the wheels. Keeping the T5 so gotta be careful!

 

Members of this forum pretty consistently make 270 RWHP with stock 5.3L LS swaps. Cammed 5.3L are making somewhere between 310 - 340 RWHP. These are all nice drivers, not max effort.

 

​​​So in one hand you have a running 5.3 LS that you know the history. And in the other hand you have $1,800 that you could hand over for an old LT1 that you don't know how many problems it has.

This is a no-brainer.... keep the engine you have and know.

Why does your 5.3 need a rebuild? The iron short blocks usually last a long long time. There are countless stories how people would have been better off just leaving the stock short block alone.

 

I wouldn't waste my time w an LT1. They just have too many unique parts and systems. Id either use a OG sbc w some good heads/efi or a simple 5.3. But you need to figure out how to get the t5 bolted up w the proper angle and check out the pilot bearing recess in the crank.

i completely agree w 3-350hp statement. These cars are a blast w around that hp. The drivetrain can (kind of) handle it. The body wont twist too much. And the cars are just really fun at that power level.

 

Your Gen III/ IV SBC 5.3L can easily make 300HP at the wheels!

That's only around 375HP at the Crankshaft to get 300HP through a 5-Speed.

An Aftermarket Camshaft with Valve Springs and corresponding parts ONLY on your stock 799 Cylinder Head 5.3L is very easy to do 375HP...
The bigger problem is going to be keeping a Stock Non-World Class T-5 5-Speed Transmission together!!!

Making the Horsepower is the easy part! Cam ONLY!

 

For what it's worth, i had a 355hp/410tq zz4 runing through a t5 w a 3.23(?) open rear w 275/40-17s. It held up for years w cautious abuse.

 

A 450-500 hp 383 is about like falling out of a tree and hitting the ground today even with a cam that has near factory drivability. Some of Karl Ellweins LT1s are getting there even with 350-355 cubic inches using ported factory aluminum heads. I have seen several of them make 400 whp with just a cam and ported stock cylinder heads using the factory bottom end. Vortec 350s are not that much different in power or lower end strength.

 

~330 crank, IMO. It's way closer to ~10% through a stick...especially an efficient one like a T5. Which just makes meeting the goal even easier.

 

Sorry for the delay in reply. The 5.3 was using/leaking oil and needed a qt every 2-3 days. We were an environmental hazard! My son really wanted to upgrade to a 6.0 in the truck, so that's why I have the LS.

However, I picked up an 84 z28 complete with 305HO and T5, no title, for $1000. But now I have a better windshield, the white 5 spoke mags, plus the engine and tranny. I'm just gonna build the 305 out closer enough to 300 crank HP so it will still be fun, but not crazy expensive and not likely to tear up the T5. And install will be a lot easier than making the LS fit.

And who knows, maybe someone wants to buy a roller Camaro with an LS to be swapped and I come out ahead!

 

Sure on a generous chassis Dynomometer, or with a generous power correction factor. Definitely.

However, when you build and sell these Power-Train systems, the work must stand up to the most scrutinizing Dyno Systems.

 

Right? Buuuut..."generous dynos" is the same as saying 15% is too much. Put another way, if most dyno's are "generous"...then that is the standard. The norm. You can't have generous dynos, then add 15% arbitrarily, and have some big bad CHP number and have that be accurate or mean anything. So let's look at a few cars that I've experienced, that have had SAE Cert'd crank numbers on a factory dyno as installed:

I've dyno'd 4 different GM cars on 4 different Dynojet Dyno's. Knowing that
"when you build and sell these Power-Train systems, the work must stand up to the most scrutinizing Dyno Systems"...in other words, GM's (all OEM's) Net CHP ratings have to be accurate/credible, let's review the following:
*Box stock 2006 C6 base/6 speed. 366 RWHP. That's 8.5% (on two dynos)*
*Box stock 1992 C4 base 6 speed: 279 RWHP. That's 7% (on two dynos)
*Box stock 2006 CTS-V: 338 RWHP. Now that's 15%. *(Same as second dyno for the C6) Why is that 400hp stick shift car show a lower RWHP #(greater DT loss) than the other 400hp stick shift car? Drivetrain mass. The Cad has that 45 lb flywheel, a 40lb drive shaft, big heavy rear wheels, heavy 6 lug hubs and heavy 14" rear rotors. Few 3rd gens have drivetrains like this car.
*Dual exhaust/no cat/no smog pump, L98: 241 RWHP. IDK...what's the crank hp on an L98 w/duals no cats and free mods? ~265? 7.4% Forget that one if you like, but you can see a trend here. If all those dynos "read high"...then that's the standard and thus the drivetrain loss is what it is.
Put another way, is it fair or realistic for me to take the C6 or the C4, run 366 or 279 wheel and say that I have a 430chp* stock LS2 C6 and a 327chp* stock LT1 C4? Of course I never owned either of these cars.

*430chp-15%=366RWHP and 327chp-15%=279RWHP


So...IDK. If dynos "read hi", then they ain't no 15% loss, either. Because a 300net crank motor isn't 327net crank

 

It's interesting, both the dyno operator and the tuner who did my car said w my drivetrain they expected 15-18% loss. I have a t56 and a 9in w big brakes/wheels. That was w a dyno jet. They both said the 9in is big/heavy as is the t56. I could see 10% on a loose t5 w a stock rear.

 

Not just 383 Engines, but 350 Engines as well!

My TGO Account Name was chosen because in the Late 1990s and Early 2000s, we did a ton of L31 Vortec 350 Swaps!
We build them from mild to wild...

Our most popular version was basically a Camshaft, Rockers, Intake, and Induction ONLY on a Stock Rebuild.

Essentially:
-Cylinder Block smoothed/ deburred, threads chased, oil passages optimized, and Zero Decked with custom designed Cam Bearings.
-Machine work for ARP Main Cap Studs (with Line-Hone, clearance and install new Bearings).
-Machine work for ARP Connecting Rod Bolts/ Nuts (with smoothing/ deburr and shot-peening, clearance and install new Bearings).
-Smooth/ deburr Crankshaft.
-Smooth/ deburr Pistons (with Filed/ sized new Piston Rings).
-Re-balance Rotating Assembly.
-New Modified Oil Pump and Pick-up.
-New True Double row Roller Timing Set.
-New MLS 0.040" Head Gaskets.
-Custom Camshaft and Valve Springs.
-Full Roller Rocker Arms.
-Machine and Port Heads.
-Edelbrock Performer RPM Air-Gap with drilled Injector Bosses.
-Throttle-Body and Elbow adapter for 4150 Flange.

These would make a solid 500HP all day long!
Some we Turbocharged and made 700HP - 800HP with stock Rotating Assembly (would not handle a Supercharger or Nitrous).

We also did a GMPP Fast-Burn Head version of this build that was good for another 60HP - 70HP (with different Camshaft).

Good times!