ls3 heads and intake? worth the trouble?
Thread Starter
Teching In
Joined: Jun 2016
Posts: 18
Likes: 0
From: NH
ls3 heads and intake? worth the trouble? Hello
I'm gonna be stabbing a 5.3 in a 89 s10.. as cheaply as I can..
What's needed to use an ls3 intake with a harness made for truck intakes and injectors?
Would I be better off getting a harness for ls2 intake and injectors?
I only ask cause, after I blow this 5.3 or next spring (which ever comes first).. I wanna swap the 5.3 out for a 6.0 with ls3 heads and intake..
thanks to any ls engine guru's who help
I'm gonna be stabbing a 5.3 in a 89 s10.. as cheaply as I can..
What's needed to use an ls3 intake with a harness made for truck intakes and injectors?
Would I be better off getting a harness for ls2 intake and injectors?
I only ask cause, after I blow this 5.3 or next spring (which ever comes first).. I wanna swap the 5.3 out for a 6.0 with ls3 heads and intake..
thanks to any ls engine guru's who help 
Pretty sure an LS3 intake won't work on a 5.3L, ports are different and wont match.
LS3 heads wont work on a 5.3L. Bore isn't big enough to clear the valves on the LS3 heads. Has to be 6.0L or bigger.
Harness for LS2 & LS3 should be the same.
LS3 heads wont work on a 5.3L. Bore isn't big enough to clear the valves on the LS3 heads. Has to be 6.0L or bigger.
Harness for LS2 & LS3 should be the same.
Thread Starter
Teching In
Joined: Jun 2016
Posts: 18
Likes: 0
From: NH
Thanks samckitt for replying..
I know the 5.3 has cathedral port heads vs the ls3's rectangular port heads..
I found some machined plates on ebay (probably junk) that allow you to bolt ls3 port intakes on cathedral port heads..
Do you think it'd be a good idea to Set up the 5.3 to run an ls3 intake, injectors and a larger cable tb? So later when I swap in a 6.0 with ls3 heads, I'll already have an intake and fuel system covered??
I know you need a 4 inch bore to run ls3's..
If I end up just using the truck intake and stuff, and order my harness for a truck engine... what's involved in switching over later to ls2/3 intakes?
I know the 5.3 has cathedral port heads vs the ls3's rectangular port heads..
I found some machined plates on ebay (probably junk) that allow you to bolt ls3 port intakes on cathedral port heads..
Do you think it'd be a good idea to Set up the 5.3 to run an ls3 intake, injectors and a larger cable tb? So later when I swap in a 6.0 with ls3 heads, I'll already have an intake and fuel system covered??
I know you need a 4 inch bore to run ls3's..
If I end up just using the truck intake and stuff, and order my harness for a truck engine... what's involved in switching over later to ls2/3 intakes?
Restricted User
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
I don't think you would see gains with that LS3 intake that would justify the cost and hassle.
The LS2 intake makes less power and torque than the truck intakes.
Get a new style or TBSS truck intake. They fit under an S10 hood and make more power/torque than any other cathedral port intake.
The LS2 intake makes less power and torque than the truck intakes.
Get a new style or TBSS truck intake. They fit under an S10 hood and make more power/torque than any other cathedral port intake.
Thread Starter
Teching In
Joined: Jun 2016
Posts: 18
Likes: 0
From: NH
I wouldn't really be looking for any power gains if I went with a ls3 intake.. I was also thinking about a holly hi ram for ls3 style ports..
I know I'll loose ALOT of my bottom end but i would think i could miss alot of it with a good stall.. plus it'd be good for a 6.0.. right?
Just wanna be able to use it later with ls3 heads..
The way I'm thinking, I could stab in this 5.3 with adapters for the ls3 intake, have the harness made for an ls2 intake and injectors, use all the appropriate injectors,tb etc...
Then next year I can just pull the intake off the 5.3, set on the 6.0 with ls3 heads and bolt the intake down, hook up the sensors and be able to run the new engine with a tune??
Am I thinking wrong?
I just don't wanna spend a lot on a ls2 intake,injectors,rails and a 4 bolt tb to only be able to use the tb on an engine with rectangular port heads..
other then a cam I don't really wanna spend a lot of money on this 5.3..
I'm only using a 5.3 cause it was free, otherwise I would have purchased a 6.0 and some ls3 heads (saving that for next year when I have the cash)
I know I'll loose ALOT of my bottom end but i would think i could miss alot of it with a good stall.. plus it'd be good for a 6.0.. right?
Just wanna be able to use it later with ls3 heads..
The way I'm thinking, I could stab in this 5.3 with adapters for the ls3 intake, have the harness made for an ls2 intake and injectors, use all the appropriate injectors,tb etc...
Then next year I can just pull the intake off the 5.3, set on the 6.0 with ls3 heads and bolt the intake down, hook up the sensors and be able to run the new engine with a tune??
Am I thinking wrong?
I just don't wanna spend a lot on a ls2 intake,injectors,rails and a 4 bolt tb to only be able to use the tb on an engine with rectangular port heads..
other then a cam I don't really wanna spend a lot of money on this 5.3..
I'm only using a 5.3 cause it was free, otherwise I would have purchased a 6.0 and some ls3 heads (saving that for next year when I have the cash)
Restricted User
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
Or you could not waste money on any upgrades at all, buy a $200 ebay GT45 turbo, and make more power than an LS3 topped 6.0 could ever think of. You could have it done and running for the same price (or cheaper) than the 6.0.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0
Brett Foote
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever
Verdad Gallardo Thread Starter
Teching In
Joined: Jun 2016
Posts: 18
Likes: 0
From: NH
Damn.. now you really got me thinking! I just find the truck intakes ugly tho..
thinking about a buying cathedral port holley hi ram and boosting it like you suggested..
Truck doesn't have a/c or power steering so if I buy a electric water pump, the only accessorie I'll need is an alternator.. so that should free up a couple ponies..
thinking about a buying cathedral port holley hi ram and boosting it like you suggested..
Truck doesn't have a/c or power steering so if I buy a electric water pump, the only accessorie I'll need is an alternator.. so that should free up a couple ponies..
Thread Starter
Teching In
Joined: Jun 2016
Posts: 18
Likes: 0
From: NH
And I'm kinda worried about buying one offline and having it fail/ be done badly.. are they're any trusted sources for shaved truck intakes..?
Thread Starter
Teching In
Joined: Jun 2016
Posts: 18
Likes: 0
From: NH
So I found a shaved truck intake on ebay thats been hot tanked and is all ready to hydrodip.. but it's $250.. is that a good price?
I suppose I could look around town for another truck intake to try and shave myself, so if I mess it up I'll still have the one that's already on the engine..
I suppose I could look around town for another truck intake to try and shave myself, so if I mess it up I'll still have the one that's already on the engine..
Thread Starter
Teching In
Joined: Jun 2016
Posts: 18
Likes: 0
From: NH
Well I found another truck intake..
my cousin has a parts truck and he said I can have the intake,injectors,injector rails and throttle body for 50 bucks..
So I'm gonna try shaving it this weekend and if all goes well I'll be using it on the 5.3..
my cousin has a parts truck and he said I can have the intake,injectors,injector rails and throttle body for 50 bucks..
So I'm gonna try shaving it this weekend and if all goes well I'll be using it on the 5.3..
Teching In
Joined: Jun 2016
Posts: 2
Likes: 0
From: Colorado
From what I understand, the LS3 heads need a minimum of a 4" bore to work. Even on LS2 applications, there are issues with valve shrouding, as the valves on the LS3 head are much bigger than that of the LS2.
If you are looking for heads on the cheap, a quick search of your local junkyard for something like the 799 casting could prove worth while. The 799 head is similar to the LS6 (243) head, with exception to the valve material. You could even have them ported, some companies have seen some incredible power figures through a ported set of 243/799 heads.
Good luck!
Luke
If you are looking for heads on the cheap, a quick search of your local junkyard for something like the 799 casting could prove worth while. The 799 head is similar to the LS6 (243) head, with exception to the valve material. You could even have them ported, some companies have seen some incredible power figures through a ported set of 243/799 heads.
Good luck!
Luke