GaryMccolley

So I am new to LSX motors. rebuilt loads of 350's back with my dad growing up. Was able to land my self a complete 2003 truck with the 4.8L LR4 in it, motor tranny were free after selling a lot of parts off of it.

So this motor and tranny are going into a 69 C10 SB truck. I would like to build it up some but not go crazy during summer it will be driving a fair amount.

The Book I have says the 4.8/5.3 blocks can be punched out 3.779"(96mm) to 5.7l 3.893"(99mm) This would be taking .119 out of the cylinders which seems to me a lot. Is this a wise thing to do.

ok second question is is the stroke the same in the 5.3 and 5.7( same crank and rods) just different cyliner size?

Now on to heads they are 862 worth messing with making any power with The plan is putting eather a ls1 or ls6 intake on the motor to clean it up a lot. along with some good headers.

In the end 350-400 HP is my target on power think beyond that I should just get the 6.0L and work with it problem with that is they want a lot for LSx motors around here about a 1000 for a 4.8/5.3 arount 75k miles on it in wrecking yards.

Thanks Gary

KCS

iTrader: (20)

Sure is. People do it all the time. You can actually go a little further to 3.905" or so for 347ci.

Nope, the 4.8L cranks have a shorter stroke than the rest of the LSx engines, so the rods are different as well, but the bore is the same as the 5.3L engines.

400hp should be a piece of cake with 347ci but you may need more than just aftermarket headers and an LS6 manifold. The 862's should be adequate but you'd probably need a larger cam and an appropriate valvetrain to make that power level. A good valvejob would only make it that much easier to achieve 400whp.

GaryMccolley

Thanks for the info

Where would be a good place to get a basic 5.7 rotating assembly(crank, rods and pistons) from?

Also KCS what is a good valve job on the heads? This is a very basic question but what would be a good cam to use and what vavle train parts need changed

And yet another question is about the ECM is it something that can be basic tun for a motor just of the specs of the parts going into it? or is it something that needs to be put on a dyno and ran. There is a motor dyno not to far away but no chassis dyno. Also dont know if they have anyone that know how to tune the LSx motors there.

Sorry for all the questoin learning curve on the LSx motor is kinda high when you know no one around that works on them.


Gary

garygnu

some 5.3 blocks can be bored out to 3.908.schwanke engines or TSP are good places to start when looking for rotating stuff.the 4.8 stuff mite be fun if dealing with turbos and super chargers.

GaryMccolley

Who is TSP? Found schwanke engines web site.

180ls1

iTrader: (4)

unless you are going to run boost i would look into one of the 6.0l engines bacause of the mod potential. Like a lq4 lq9, they free up a lot of options for better heads and more cubes. I know its not what you were asking but if you are going to sink money into a N/A motor i would not use a 4.8

TSP is texas speed and performance

GaryMccolley

Ya I know what you are saying and with i could do that but around here 6.0L i bet would be 1500 in a wrecking yard. I will call around and find out what one would cost and give you guys an idea.

Called about a 4.8L and it was 900 for a 110k miles to 1200 for the 75k motor.

really sucks when i see people put you can pick them up for 600 or so other parts of the US