taylor8907

Hey Guys,

I bought a motor a few months back for a project off craigslist, was told it was a 5.3....ended up after swapping a new cam, springs, oil pan, and intake manifold that i have a 4.8.

From what I have read so far, the only difference in the two is the stroke...Rather than undo all the work I have put into this motor so far, is it possible to put in a 5.3 crank and connecting rods and leave everything else?

Thanks for any advice, this is in an attempt NOT to have to buy another motor and put all my parts and stuff on that one. Dont have the space for it and I found rods and a crank relatively cheap locally.

Thank you

luigiandme

iTrader: (2)

Everything needs to be changed. Cranks Rods Pistons

gmoutdoorsman

I thought the crank was the only difference? Thought the used same rods. Same bore but 5.3 has flat tops

taylor8907

I was under the same impression, that the bore is the same just the 4.8 pistons are flat and 5.3 are dished previous to 2004. so the pistons should be the same, only crank and connecting rods would be different...Would the crank position Sensor still work?

taylor8907

Any mechanics around that can offer any advice?

truckdoug

iTrader: (25)

crank, rods and piston dishes differ, blocks are the same bore wise

pin height is the nearly identical between the 4.8/5.3

post #7
http://www.performancetrucks.net/for...-5-3-a-431486/

lilaaron233333

iTrader: (10)

why not jsut sell the 4.8 n buy a 5.3 for just bout the same price insted of goin thru all that work of switching the parts.

truckdoug

iTrader: (25)

or put the boost to it until it pops like the HRM 4.8...
http://www.hotrod.com/techarticles/h...g_bang_theory/

but yeah lilaaron233333 is right. easier to find a fivethree than swap all the stuff around.

BLK95-Z

iTrader: (2)

Flat top 4.8 pistons are an upgrade in a iron 5.3 as it would raise the compression a bit. The 4.8 has longer rods because of the shorter stroke. You would need to change the crank and the rods.

4.8 = 3.27 stroke, 6.278 rod length, and 3.779 flat top piston
5.3 = 3.622 stroke, 6.098 rod length, and 3.779 dished piston

truckdoug

iTrader: (25)

so 5.3 crank and rods, 4.8 pistons right?

what kinda CR would that yield?

BLK95-Z

iTrader: (2)

Correct. Make sure they are from the same generation

10.0:1 with 243/799 heads (same as the L33)

truckdoug

iTrader: (25)

Sorry to keep this limping along...
so it'd be a little higher with "truck" 853 heads?

I am brand new to the ls motors.

BLK95-Z

iTrader: (2)

853 are ls1 heads off of a car and compression would be a bit lower than the 243/799 heads (66cc vs 64cc)

852 and 706 are truck heads with a smaller chamber (61.1cc) but also have smaller valves and runners.