We've been working on bringing a CNC ported aftermarket head to the guys and gals who want to hot rod their 5.3l engines and not deal with swapping a 6.0l engine. I've always felt the small bore LSx engines have been left behind by the aftermarket cylinder head manufacturers. Therefore a special thanks to Edelbrock for making a versatile head casting to allow this accomplishment.
This is welcome news for those wanting to spice up their 4.8l/5.3l N/A or blown engines. We worked hard to bring an exhaust port configuration that will make any and all blown 5.3l engines happy.
I just got done flow bench testing the production ready CNC program for the 4.8l and 5.3l LSx engines.
Here's some stuff fresh off the flow bench. All ports on one head were tested and the following info is an average of the tested ports. FYI there was less than 1% difference between the tested ports.

Valve sizes: Intake = 2.00" Exhaust = 1.570"
Test bore dia. = 3.780"

Lift_____.100"__.200"__.300"__.400"__.500"__.550"_ _.600"__.625"
Intake__65.0___131.8__193.5_235.3__267.4__277.0__2 84.9__286.9
Exhaust_58.7__120.6__167.6__205.2__228.5__234.5__2 38.1__239.7
The exhaust was tested with a 1 7/8" X 2.5 stub pipe.
Here's the exhaust port without a pipe:
No Pipe_63.6__115.9__164.6__192.1__209.8__214.6__217. 5__219.4

The intake runner volume is 201cc.
The exhaust runner volume is 82cc
The combustion chamber volume is 59.0cc

Here's a stock head flow test for comparison:
Intake__65.2__134.5__188.7__207.3__218.36__221.2_2 24.0__225.2
Exhaust__53.0__99.8__129.8__153.6__165.5__171.2__1 75.1__176.6
Exhaust tested without pipe.
The intake runner volume is 205cc.
The exhaust runner volume is 79cc
The combustion chamber volume is 61.0cc

This CNC port program out flows a ported production head by no less than 5-15% and has less than the production head's runner and chamber volumes.
We hope to get some dyno data to share in the next several weeks. Stay tuned...........
Our production schedule is to start shipping orders in 2-3 weeks. The initial cost per pair is $1990.00. We'll hold this price for a limited time. The heads are supplied with Comp Cams single springs (26918) and steel retainers and Viton valve seals. Dual springs will add $145.00 per set.
I'll get some info up on the website as soon as I can.
In the meantime, call us at the shop or PM me with any questions you may have.

Richard

 

Damn, nice numbers.

Richard, my heads go on this weekend (finally), and I'm back to the dyno on the 20th to test them out.

 

Great to see your progress Tom. I'm looking forward to seeing your results.

Richard

 

those look like great numbers.... I'll have to keep you guys in mind if I ever do decide to do a set of heads on this thing...

 

I wish these were ready when I was working on my Tahoe last December

Good job Richard, looking forward to seeing some HP results.

 

I have seen these heads in person

I think it might be time for an upgrade

 

Those are some real nice flow numbers on that small bore. Are these gonna be carb approved like that AFR's are?

 

I'm checking into CARB certification. It's a byzantine process and will take some time (and $) to meet.

Richard

 

keep us updated man!! if i ever need some heads then this is where ill be looking

 

No kidding, f'n california.

I would have thought that Edelbrock would have taken care of that though.