I am so happy, you can't even believe it. Ever since the L92 heads came out, a lot of people think that a cathedral port head can't keep up. I didn't believe it and neither did Tony Mamo from Airflow Research (AFR). I own a 2009 Pontiac G8 with a 6.0L L76 engine. With ARH 1 7/8" headers, FAST 102 intake, Yella Terra 1.85 rockers, ASP 25% UD pulley, and Vararam CAI, the G8 made 397rwhp/395rwtq. This was one of the higher dynoing bolt-on 6.0L G8s. Most 6.0L G8s make in the 420-440rwhp range with bolt ons and a 230/238 cam. The highest number I've seen for a 6.0L G8 automatic has been 470rwhp and this one had ported L92 heads.

Tony Mamo and I decided to go "old school" and take off the Gen IV L92 heads and install a set of AFRs brand new 230 V2 heads. We called this our "Back to the Future Project". I had these heads milled to 65cc chamber so they matched the cc volume of an LS2 head (11.0:1 SCR). Then Tony Mamo did one of his famous porting jobs on a cathedral port FAST 102 intake. We used a fairly mild 231/231 .617/.617" 114LSA +2 advance Comp LSL cam. The gains were staggering: 504rwhp/440rwtq. A gain of 107rwhp/45rwtq. Keep in mind, this is through a locked-up automatic. Most people think that there is little to be gained over L92 heads, but thanks to the huge flow numbers and high airspeed of the AFR 230 and the "mamofied" FAST 102, substantial gains can be had.

There is still more power to be gained with a 102mm throttle body and larger airbox as we were pulling 5-6 kPa vacuum at WOT. Stay tuned for more details on the "Back to the Future Project". There's another 10-15rwhp to be gained with reducing inlet restrictions.

Edit: On 9/12, we added some 2.5" clone Magnaflow mufflers, replaced the MAF with a 4" pipe, and ran with the converter locked and unlocked. As you can see on the second graph, the Yank 3200 converter is very efficient. We are still pulling a 3-4kPa vacuum so the 102mm TB is next. My goal is to be over 500rwhp with unlocked converter and full exhaust. We are only 3rwhp away from the goal now.

 

WOW Patrick Congrats..
and like always great work Tony those new AFRs making serious power.

Patrick Graph is not showing for me??

 

Here's a You Tube video of the dyno pull:
http://www.youtube.com/watch?v=IZBy3TT9QQg

 

wow man. very impressive. nice results and congrats on the new power

 

Its a dynojet right?

Very close numbers to your old WS6

 

very nice results.

 

Thats just awsome. Great job again for you and TOny.

 

Sweet!

Keep us updated.

 

Strong #'s-4 door super sleeper!!

Was your G8 running the stock cam before the head swap?

 

So, 500 rwhp 6.0's now? Oh, with Automatics....?

Time to go rewrite the rules again....!

You think there are a few 383/408/M6 guys that are going to come in here and scream bloody murder?

Excellent build guys.

 

I guess I was wrong Patrick. NO WAY did I think you'd make this much power with that setup when we first talked about it.

Nice.

 

V-Nice results,

did u guys remove l92 and put on 230 on the same car ?

 

Yes, I was running stock L76 cam with 1.85 ratio Yella Terra rockers in the 397rwhp dyno. On the 504rwhp dyno I was running stock LS2 1.7 ratio rockers. The Yella Terras would not have worked because they had the offset intake rockers plus they would have put the lift over .671".

I agree Mike. We're always talking 'til we're blue in the face about spending the real coin on the best intake/head combo because that's where the gains are going to be found. Tony Mamo's intake manifold porting is so good, that we're getting a net 310+cfm at .500" lift through the heads and into the cylinder. Another thing, going from a 260cc port to a 230cc port makes the air speed soooo much higher. Throttle tip-in is much better with these heads compared to cammed LS3's I've driven.

 

So when does your 6.2 Yukon get the same treatment???

It does not look like there was any low end torque loss, which should make this a pretty sweet combo for any big, heavy vehicle.

 

congrats on some great results Patrick and Tony

 

another question how will the 230 v2 performe on a 5.7L engine.

 

Funny you mentioned this. I have already talked with Tony about this. Imagine a high flow cathedral port head with the tall FAST truck intake and variable valve timing? The Denali would be a 3 ton rocket! My wife said she'd rather have new furniture for that kind of money so the project may take a while to get off the ground, LOL.

 

Uggh, furniture?
Cant you park that Denali in the living room??

But wow, I did not even think about the long runner Fast truck intake....and VVt...ok, now you HAVE to do it

 

There's yardsales everywhere this time of year....go get her some furniture..

 

I like your way of thinking.