I was just looking at my new 2008 RCSB 5.3 Iron Block/Flex Fuel truck, and it has 243 heads on it. I thought that was a bit strange, seeing as how I thought all the 243 heads were for the larger bore 6.0's. Does this sound strange to anyone else?

 

they started putting them on the 2007 nnbs...

 

thats cool

 

And the NNBS 6.0s get the L92 heads

 

Are these heads also on the 4.8's

What is different on the 4.8's versus 5.3's to give the 5.3 20hp and 30ft/lbs of tq more than the 4.8?

 

More cubic inches

 

What else is different between the truck 243 and the ls6 243 heads besides valve size?

Can we run the larger valves with small bore engines?

 

And the stroke is different too....but do the 4.8's get the larger throttle body and did they get the 243 heads too?

btw.....send me info on the factory wheel hookup

 

JB, yes. The 4.8's-the 6.0's get the 87MM throttle bodies. I know my 4.8 came with the 243 heads too, I can't speak for them all, but I would assume so.

 

all 07 4.8s and 5.3s come with 243s or either 799 wich are both ls6 style heads