deucesallin

Im looking to build an oem style high compression 5.3 with a Gen III block...

The GenV stuff is so nice- will these valve reliefs line up with earlier 5.3 heads?

11:1 CR in my '14 L83

deucesallin

Is it a dumb question? I did the google.

I get conflicting stuff on actual CR of the 2014 DI 5.3 (11 or 11.5:1?), however I know the pistons are notched and that they sound nicer than the stock 4.8 pop-ups the older 5.3 guys are swapping to add compression.

JoeNova

I'm pretty sure the Gen 5 engines use the gen 4 connecting rods, so no issues there.
That also means the pistons will technically fit, although I'm not sure if compression height has changed.

MuhThugga

They reversed the intake and exhaust valve positions on the Gen V head, so the valve reliefs may not line up with a Gen IV head.

You can also use a 4.8 flattop piston and smaller chamber heads to get the compression up. The flattops were also used the the Gen III L33 and the Gen IV 5.3s.

deucesallin

hmmm...

I guess it depends on whay the new pistons loom like compares to the oem 4.8s...

MuhThugga

The OEM 4.8 piston is a flattop with no reliefs.




I don't know what the L83 pistons look like having never seen one in person, and too many different pistons pop up when I try searching for one.