4.8 with a cracked head question...

[Puropedo]

Hey guys Im looking at a 4.8 that seems to be in good shape but the drivers side head is cracked where the exhaust manifold bolts on because of an accident, would this be an easy repair as for just buying a good head and bolting it on? Are the 4.8 and 5.3 heads the same? The number casting on the heads are 862 if that helps.. Any advice is welcome, thanks in advance.

[CamaroChris]

I think that you could just find another 5.3/4.8. They are so cheap to come by. To fix it, you'll be another 300$ on top of the price . Just buy a different one.

[Clyde65]

I wouldnt buy it unless it was like <$100. if not, then I would agree with Chris above, move on to a known good motor. if the accident caused the head bolt hole to crack, what other issues are you facing?

[6.0 1955]

It's ultimately up to you but the 5.3 and 4.8 heads are the same. But if the engine is early 2007 and older then you are looking for 862 or 706 casting heads. The newer engines run the 243 and 799 casting numbers which are the same as ls2 corvettes and LS6 engines. If you look around older 5.3 and 4.8 heads can be found for around $50 a piece or if you get lucky a buddy may even give you one. You will then need head gasket and head bolts to complete the job. Another option is take the head and have the area welded.

[Puropedo]

Hey guys thanks for your replies, the engine or I should say drivetrain comes complete with tranny, all the accesories, harness and ECU, even the exhaust flanges with the oxigen sensors, all this for a pretty good deal, owner didnt know head was cracked till we unbolted the exhaust manifold (two bolts were broken, so I had to inspect)...

Originally Posted by 6.0 1955

It's ultimately up to you but the 5.3 and 4.8 heads are the same. But if the engine is early 2007 and older then you are looking for 862 or 706 casting heads. The newer engines run the 243 and 799 casting numbers which are the same as ls2 corvettes and LS6 engines. If you look around older 5.3 and 4.8 heads can be found for around $50 a piece or if you get lucky a buddy may even give you one. You will then need head gasket and head bolts to complete the job. Another option is take the head and have the area welded.

This is what I kinda wanted to hear, thanks! Im prettry sure I could find a good head around town, wasnt really sure if 4.8 or 5.3's heads were the same...Now, since it has a good 862 head on it and if I were to find a good 706 would it be ok to mix and match? Or, does both heads need to be the same #? Does it matter if its the drivers or passanger side? Sorry if this are dumb question but Im starting to get familiarised with the lsx engines and Im pretty sure someone else will benefit with this valuable info as well....

[6.0 1955]

The 862 and 706 heads all have the same cc on the combustion chambers and have the same size valves on the intake and exhaust. The heads are also interchangeable side to side. So if you find a head from a pre-2007 5.3/4.8 engine you will be good to go. Just a reminder the head bolts on these engines are torque-to-yield bolts and should only be used one time. The bolts also have a specific tightening sequence and it is not a ft-lbs type of tightening. If you purchase ARP bolts they are torqued to a specific ft-lbs rating. There are no Dumb questions especially when trying to learn a new type of engine configuration!!!! I'm just lucky a couple of my friends have a chassis dyno and perform swaps and tunes for our tri-state area. So my knowledge was gained from the time there and my own trial and error.

[Clyde65]

May I ask what he is asking for the motor? with all that stuff included, it might be worth picking up if he is willing to deal.

The 4.8/5.3 heads are pretty easy to find, so it might be quite do-able.

[Puropedo]

Originally Posted by 6.0 1955

The 862 and 706 heads all have the same cc on the combustion chambers and have the same size valves on the intake and exhaust. The heads are also interchangeable side to side. So if you find a head from a pre-2007 5.3/4.8 engine you will be good to go. Just a reminder the head bolts on these engines are torque-to-yield bolts and should only be used one time. The bolts also have a specific tightening sequence and it is not a ft-lbs type of tightening. If you purchase ARP bolts they are torqued to a specific ft-lbs rating. There are no Dumb questions especially when trying to learn a new type of engine configuration!!!! I'm just lucky a couple of my friends have a chassis dyno and perform swaps and tunes for our tri-state area. So my knowledge was gained from the time there and my own trial and error.

Hey man, I really appreciate your help. I found a good head off a 5.3 706 casting #, do i need to refurbish it? It seems to be in good condition, also does it just "bolt in" or is there anything I should know when I get ready to install it? Again thanks for all your help.

Originally Posted by Clyde65

May I ask what he is asking for the motor? with all that stuff included, it might be worth picking up if he is willing to deal.

The 4.8/5.3 heads are pretty easy to find, so it might be quite do-able.

I ended up buying the drivetrain from the guy, he let it go for $800 (originally asking $1200) drivetrain has 84k original miles...

[6.0 1955]

Getting the 706 checked out is up to you. I have a couple of good buddies that have machine shops so I always take them in and have them cleaned and looked over. Your other question about installing you need head gasket, head bolts, and tightening sequence for the type of bolts you use. That should really be all for installing the head. You can reuse the rocker arm bolts and get the proper torque specs for those it's around 22-24 ft-lbs.

[Puropedo]

Originally Posted by 6.0 1955

Getting the 706 checked out is up to you. I have a couple of good buddies that have machine shops so I always take them in and have them cleaned and looked over. Your other question about installing you need head gasket, head bolts, and tightening sequence for the type of bolts you use. That should really be all for installing the head. You can reuse the rocker arm bolts and get the proper torque specs for those it's around 22-24 ft-lbs.

Thanks for all your help!

[eagleuh1]

Sounds like a good deal with everything. You'll like it in your truck. Big difference. Jim