First thanks for taking the time to help. I have a 08 5.3 vin J motor. the part number P/N 12615363 LS6 Production Cylinder Head - Bare Fits any 1997-2007 LS Family engine
• 210cc “Cathedral port” intake ports
• 70cc D-shaped exhaust ports
• 65cc combustion chambers
The cylinder head I want to put is P/N 12582714 L76/L92 Cylinder Head Bare,
Aluminum performance head
• Higher flow than cathedral port LS heads
• Fits any LS family engine with 4.00" bore or larger
• Uses 2.16" solid stem intake, and 1.59" solid stem
exhaust valves
• As-cast “rectangle port” intake ports (not compatible
with LS7 intakes)
• D-shaped exhaust ports
• As-cast combustion chambers
What I need to know is will these cylender heads fit or bolt to my 5.3 motor. Any help would be greatly appreciated. dont really have time to search through all the old threads with my work schedule. Thanks again, Kenny

The pic is of my late great and saddly missed 03' Z71. Im sure you can usderstand where im goin with the new one.

 

i thought you needed a minumum 4.00 bore to run l92's

 

If that is the case then can you punch a 5.3l to a 4.OO bore?

 

Ditto, slap some worked ls6 heads on there, or stage 2 heads from tsp, wcch. Why go threw all the trouble of punching out the engine, when ya can get heads that flow just as good as the 92's ???

 

will not work.

 

WOW 2.16 intake valve, isn't that on the huge side?

 

A 4.8/5.3 block can be bored to a LS1 bore but not a 4.00. The valves are too large in the L92's and would hit the cyl wall on anything smaller than the 4.00"

 

Yep the 5.7/6.0 use a 2" intake valve. The LS7 uses a 2.20" intake valve

 

as stated it will not work with the small bore. besides everyone gets all dick hard over the CFM numbers on the l92 heads. . .reality is you need to see the relationship between intake and exhaust flow in percent wise vs port volume