From “Polk” on 'Tuners: http://www.dsmtuners.com/forums/showthread.php?t=173572
”+1mm valves will hurt power unless the head has been worked over and running bigger cams. The stock size (aftermarket) valves will out flow +1mm at lower lifts (up to .350 lift).”
DCobb -NABR Regular: http://www.teamnabr.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=004487#000000
“The cylinder head from a 4G6 has some of the best flowing ports in the industry. It's one of the main reasons I went with a DSM platform. Unless you plan on making more than ~450whp I would leave them alone. Removing casting flash is always a good thing but that's about all I would do. Your energy would be better spent elsewhere where you run less risk of slipping with the grinder and ruining a perfectly good part.”
From Rich -NABR Veteran: http://www.teamnabr.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=002865#000001 or http://www.teamnabr.com/cgi-bin/index.cgi?page=archives.pl&action=view&topic=2865
“I ran 11.34 @ 124.55 mph in a 3060 car with me in it on a stock head/intake with an $80 valve job.
Now, with a BJ's stage 4 head and his sheet intake, best ET I've hit is 11.24 and best mph of 126.7 in a car that now weighs 2980 with me in it. I even upgraded to a massive 205 IC from the old 178 I used to run. Do I currently feel it was money well spent? Not really.
Maybe I'm nearing what a 50 trim can do–curt brown excluded of course Wink as he did hit 131 I believe–and that is why I haven't seen the gains? I'm pretty confident I can get ~128 out of the car, but I can't see much more than that without powershifting.
Either way, anyone that comes to me asking about getting headwork, I send them to my $80 valve job guy.”
Marco -NABR chief floppy head: http://www.teamnabr.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=002865#000001 or http://www.teamnabr.com/cgi-bin/index.cgi?page=archives.pl&action=view&topic=2865
“Well interesting point and good thing you brought this up.
I did have a stock head on the car when I ran the 10.0 no N20 @ 140mph and then after the N20 it went 9.62 as you all know, MPH that day was at 147 with N20.
I then put my super hyper race head on, which Nobody has yet to purchase from me. I have 2 of these heads, one is Nicks, and one is mine. the 10.0 pass was done on a dyno'd 505-510 hp after the I switched to the new head, she made 564-568hp, both runs at 30psi.
My laptop took a crap on me at the dyno and I was not able to tune it. As a result the car is pig rich at 7000 (10.8) and almost doesn't make it to 8000. there should be more in it. Am I saying she made 50+hp from a head swap? Fucking right I am, but this isn't my ordinary cylinder head, I was as shocked as anyone else. Nor is it the run of the mill engine, a guy making 300 hp will probably not get the same power out of it. The intake valves alone are 75US dollars a piece. We built them 2 years ago when I was trying to extract every last pony from the car. Attention to detail paid off, there is not one shelf stock component on the head. Valves, guides, seats, springs, base washers, retainers, and locks are all different.
As far as major porting goes, there is no 'major' porting like on a V8 head.
Then again I haven't tried it against a regular stage 3 head for comparison. So in answer to your question. Is it worth it? That depend on how fast you wanna go (Smile)”
“Unreal” -NABR Veteran: http://www.teamnabr.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=002865#000001 or http://www.teamnabr.com/cgi-bin/index.cgi?page=archives.pl&action=view&topic=2865
“Put a BJ stage 3 head on the car. Still haven't beat my old times with the stock head.”
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