Pontiac G8 2008-2010 - Head, tb, intake porting worth it???




gtp6515
11-27-2011, 07:33 PM
I am looking at going a little larger cam, and am looking at having some items ported, and maybe an ud pulley. I am at 380 whp (dynojet in 3rd gear), which from what I have seen is quite low for my setup. I talked to a couple vendors regarding head work, a little milling, hollow intake valves, and ss larger exhaust valves. I am getting approx 15 whp from one vendor, and 25-30 from another, just on the head porting. Anyone on here have any real world experience with this (dyno graphs)? If this is the case, between all these mods, I would be adding about 40-50 extra hp for about $1700, plus whatever gains from a slightly larger cam. Pat G spec'd me a 222/226 115 + 3 and 597/597(with a stock stall), so this should net me another 10-15? I also seem to read that the L92 heads dont need much head work, if any, due to them being so great to start with. Are heads worth it? It may be the larger the cam, the more increase there would be. I am sure there are a lot of great machine shops, but I have one I am very interested in. I am trying to make sure the $$$ I spend is worthwhile. Thanks so much for any input.


G8RAM
11-27-2011, 08:43 PM
L76 or LS3?

Tainted
11-27-2011, 08:49 PM
Intake and throttle body porting are always beneficial along with the underdrive pulley. Mods like this support bigger setups in the future while still making useable power now. Having your heads ported is always a great idea, be sure its done by someone reputable :)


gtp6515
11-29-2011, 10:25 PM
Looking at Landspeed for head work.

SLOW SEDAN
11-30-2011, 11:31 AM
Typically with a 6L80 you dyno in 4th gear.

Do you have plans for a higher stall then stock? I would go bigger on the cam, even with a stock stall you can run a 223/231 with no problems, you can also go higher on the lift. I assume your upgrading springs if your pulling the heads? If so look at lift in the .610-.620 range.

I would for sure do a valve job, portnig and milling. I got nice gains doing so! I milled them .030 to bring up the compression. Your correct the bigger the cam the more the airlow improvements help.

gtp6515
11-30-2011, 09:51 PM
I want to make sure I have a good dd. I ordered a 2800 stall on Tuesday from FTI. I was looking at http://www.510raceengineering.com/s2ls3-l92.html and this is a crazy amount of power for head work I would think. I am so confused about cams, and have no idea where to start. I went with a Livernois kit, and I am not thrilled with the 1c, which is my fault as it is very mild. Milling .030, will I need shorter push rods? And I do have dual springs and titanium retainers from the Livernois kit. Think I can sell a cam for any $$$ with a few thousand miles on it, or is it garbage?

SLOW SEDAN
11-30-2011, 10:01 PM
I want to make sure I have a good dd. I ordered a 2800 stall on Tuesday from FTI. I was looking at http://www.510raceengineering.com/s2ls3-l92.html and this is a crazy amount of power for head work I would think. I am so confused about cams, and have no idea where to start. I went with a Livernois kit, and I am not thrilled with the 1c, which is my fault as it is very mild. Milling .030, will I need shorter push rods? And I do have dual springs and titanium retainers from the Livernois kit. Think I can sell a cam for any $$$ with a few thousand miles on it, or is it garbage?

Yes you would need shorter pushrods if you mill the head. I used 4.375 pushrods with my heads milled .030.

Same spring kit I used so your good there.

As long as the cam is in good shape you can get some money for it. Lots of people seem to want mild dod delete cams.

gtp6515
11-30-2011, 10:04 PM
Do you agree with the 40+ from just head work? Seems extreme.

Tainted
12-01-2011, 07:03 AM
40 isnt unheard of. Thats flywheel hp btw..

Gordon0652
12-01-2011, 08:41 AM
I really would not bother with the LS3 heads on the stock 6.0, I would look into a good set of cathedral port heads(MAST, TFS...). If you are set on getting the stock heads ported, talk to TEA because they seem to be the only ones that can make the exhaust flow awesome!
That is one of the problems with these heads, exhaust flow and how close the intake valve is to the cylinder, etc....
Had i paid more attention to exhaust flow I might not have gone with my TSP LXR 285cc LS7x heads for my T/A, sure they flow 400+ but what good is that when you can't exhaust it.

Tainted
12-01-2011, 09:18 AM
http://ls1tech.com/forums/dynamometer-results-comparisons/1123842-ls2-l92-heads-makes-460rwhp-446rwtq.html

That was with cats, stock manifold, MAF, and untouched L92 heads. They can make low end power just the same if you have a well matched combo.

edmanet
12-01-2011, 01:04 PM
I have a PatG cam, Greg Good ported L92 heads, a 2800 stall, fast 102, and an RPM tune. My car made 478hp and ran a 11.40 a couple of weeks ago. I believe there's at least another 2 tenths in the combo.

A well matched combo will make good power and run good.

Greed4Speed
12-01-2011, 01:41 PM
You can't really compare dyno to dyno. I can drive across town and dyno 30-50 whp less or more depending on where I go (all dynojets). I personally wouldn't worry about dyno numbers, and focus more on how the car performs with the set up. My Camaro only made 480 whp with a 408. That was a good 20-30 whp lower than most post with a similar set up, but it still outran some cars that should have beat me based on dyno numbers so I didn't care.

To aswer your questions though, yes the porting can be worth it depending on the goals for the car. If performance is you're goal, I'd suggest a converter.

gtp6515
12-01-2011, 08:42 PM
2800 FTI on the way.

gtp6515
12-01-2011, 08:43 PM
I have a PatG cam, Greg Good ported L92 heads, a 2800 stall, fast 102, and an RPM tune. My car made 478hp and ran a 11.40 a couple of weeks ago. I believe there's at least another 2 tenths in the combo.

A well matched combo will make good power and run good.
Cam specs?

gtp6515
12-01-2011, 08:45 PM
I really would not bother with the LS3 heads on the stock 6.0, I would look into a good set of cathedral port heads(MAST, TFS...). If you are set on getting the stock heads ported, talk to TEA because they seem to be the only ones that can make the exhaust flow awesome!
That is one of the problems with these heads, exhaust flow and how close the intake valve is to the cylinder, etc....
Had i paid more attention to exhaust flow I might not have gone with my TSP LXR 285cc LS7x heads for my T/A, sure they flow 400+ but what good is that when you can't exhaust it.

I seem to read so much good info on the l92 heads. Ls2 heads are better?

Tainted
12-01-2011, 09:41 PM
Sometimes, it is really dependent on your combo. Bigger motors will obviously shine better with ls3 heads, but not to say smaller motors cant. To many factors come into play to say yes or no without all the details

edmanet
12-14-2011, 07:09 PM
Cam specs?

23x/23x .60x/.61x 112LSA +2

Ask PatG if you want more detailed info.