Injector Question
Thread Starter
Teching In
Joined: Jul 2017
Posts: 6
Likes: 0
Injector Question I just purchased a 5.3 and now am thinking I have a 4.8. The question I have is the injectors that are on the engine are 25326903, which I have been led to believe are for the 5.3 flex fuel. There is a tab on the head gasket that is stamped "4,8" and from what I can see it has flat top pistons.
Did they put those injectors on the 4.8?
Any help, guidance or resources would be greatly appreciated.
-Jon
Did they put those injectors on the 4.8?
Any help, guidance or resources would be greatly appreciated.
-Jon
TECH Senior Member
Joined: Jun 2016
Posts: 22,298
Likes: 3,619
From: Central Cal.
What year is it? The later (07-on, I believe) 5.3's do have flat top pistons. Before that, they are dished. The main difference between 4.8 and 5.3 engines is the stroke. For that reason (same bore size), they might use the same head gasket.
TECH Senior Member
Joined: Jun 2016
Posts: 22,298
Likes: 3,619
From: Central Cal.
Sounds right. Trucks went to drive by wire around 2003. So IF it does indeed have flat tops, it should be a 4.8. 5.3's of that time all had slightly dished pistons to keep the compression down.
If the seller claimed it is a 5.3 I would try to get your money back if that is a problem, as converting to a 5.3 involves a crank, rods, and of course new bearings.
If the seller claimed it is a 5.3 I would try to get your money back if that is a problem, as converting to a 5.3 involves a crank, rods, and of course new bearings.
Thread Starter
Teching In
Joined: Jul 2017
Posts: 6
Likes: 0
Would it be conceivable for a 5.3 to have 4.8 head gaskets? I just found a sensor that is only for flex fuel (some fuel comp/temp) and with the flex fuel fuel injectors it leans 5.3. I am not confident on the dish or no dish pistons, I'll take another look soon.
TECH Senior Member
Joined: Jun 2016
Posts: 22,298
Likes: 3,619
From: Central Cal.
Since the bore on the 5.3 and 4.8 are the same, the head gaskets could easily be the same also. You could then easily have a 5.3 if unsure on the piston configuration. If you could check the stroke with a wire down the spark plug hole, you would know for sure.
4.8 and 5.3 use same head gasket.
If you are looking to build it, or reassemble, we have the parts you need at the best prices PLUS if you have 862 heads and they have a notch on the deck, we are one of the only places that offer mls gaskets that will work with them.
You other question...its def a 4.8l. l59 5.3 was a flat top but didnt come out til later. it used 243 heads also.
They did have flex fuel back then also. so its possible you have truck flex fuel inj. also all 4.8/5.3/6.0 reg inj are the same, and flex fuel same way. those are good inj and can come in handy.
If you are looking to build it, or reassemble, we have the parts you need at the best prices PLUS if you have 862 heads and they have a notch on the deck, we are one of the only places that offer mls gaskets that will work with them.
You other question...its def a 4.8l. l59 5.3 was a flat top but didnt come out til later. it used 243 heads also.
They did have flex fuel back then also. so its possible you have truck flex fuel inj. also all 4.8/5.3/6.0 reg inj are the same, and flex fuel same way. those are good inj and can come in handy.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
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
Restricted User
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
The 3' borescope I bought for my cell phone was less than $5 shipped to my house.
I take it and a spark plug socket with me now when I buy engines. Plug it into the USB port, stick it in the hole. Helps spot the guys that are trying to sell a 4.8 as a 5.3 pretty easily.
I take it and a spark plug socket with me now when I buy engines. Plug it into the USB port, stick it in the hole. Helps spot the guys that are trying to sell a 4.8 as a 5.3 pretty easily.
Thread Starter
Teching In
Joined: Jul 2017
Posts: 6
Likes: 0