So I have this engine tore down to the short block and I wanted to up the horsepower a little when I put her back together.

From all I have been able to gather I can put 4.8 flat top pistons on my 5.3 rotating assembly. This is where things get weird. I've talked to several vendors jegs, summit, ebay sellers trying to get verification that this is a safe modification. None of them can give me a yes or no answer.

So I'm wondering if I bought a 4.8 engine rebuild kit from summit or jegs it should work as the only difference between 4.8 and 5.3 is the rod and stroke correct?

Has anyone actually done this or am I stuck with stock dished pistons unless I'm willing to drop 800 bucks on some forged slugs, which I'm not willing to do.

Thanks ahead of time.

 

L33 should be the pistons you want... Flat top piston 5.3l as are most gen iv engines with floating rods...as far as rebuild kits go, they should be the same as far as just about everything between the two..

 

I have a gen iii engine, I was under the impression you can't mix rods, as far as I'm aware the l33 has a different rod. Am I misinformed? Even then I don't know where I'm going to find an l33 in a junkyard

 

Everthing ive seen the 4.8 pistons fit right on the 5.3 rods no problem....

 

You need 4.8 pistons for a pressed pin application.

An L33 is a factory built 5.3L engine with Flat top 4.8 pistons.

The Vendors only know what the manufactures tell them.

There is no difference in Pin height between the 2 pistons. The difference is in the rod and crank stroke length.


If you're using 706 or 862 heads, your compression ratio will be around 10.5:1 this way.