picked up an L33 5.3L block+caps for a project motor to build. I found a brand new set of 8 replacement 4.8L pistons for really cheap. the aluminum block is going to stay the same bore at 96.01mm (+/- a few thousandths after a hone) and heads are going to be virgin 5.3L heads. I'm wondering if the wrist pin heights are the same between the 4.8L and it's 6.278" rod and 83mm crank vs the 5.3L and it's 6.098" rod and 92mm crank, so I can use the 4.8L pistons in the 5.3L block. 5.3L rotating assembly.

 

I don't remember how much different they are but they're different. Might be able to use them with some custom length rods. I think this subject has come up on here before. I think the cost of the custom length rods would be too much. Might as well buy a set of new 5.3 flat topped pistons.

 

They are the same height. They are pretty much the same piston (4.8 vs. L33).

 

Crap I could be wrong but the last time i remember this coming up i thought it was decided they were different. There is math for this. Does anyone know the exact rod length for the 4.8L?

 

i was going to do this, but last time i was told they were different, but now im hoping that was wrong

 

So I'm supposed to build a motor off of this kind of info?

Does anyone have first hand experience with using 4.8 pistons in a 5.3 or vica versa?

 

Ok, this is been covered before.

4.8 stroke: 3.27
4.8 rod : 6.276
4.8 deck height: 9.240

5.3 stroke:3.62
5.3 rod: 6.098
5.3 deck height: 9.240

Now do the math: the centerline of the cank is half the stroke of couse and the deck height is measured of the centerline of the crank.

3.62/2=1.81
3.27/2=1.635

5.3:
1.81+6.098=7.908
9.240-7.908=1.332

4.8:
1.635+6.276=7.911
9.240-7.911=1.329

So yes, they have the same pin height, give or take a few decimal place rounding in my numbers.

 

yeah i did the math on a compression calculator one day and came up with 10.3-1 compression for a 5.3 with flat tops so it would still be pump gas friendly

 

That won't work.

 

WHY??? It's only .003 diff in pin height...