Ferrea makes a 2.20 Hollow stem intake valve for L92 heads! Why no CNC'd heads w/them
11-14-2009, 03:06 PM
#24
Good point! They Carey's option is an expensive one as well. I was quoted $2200 for the intake, cnc'd (REQUIRED FOR THE L92's) and rails. Sure it's worth the $$ buts it's alot, too much for me right now.
11-14-2009, 04:48 PM
#25
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Exactly. These heads stock are manifold limited at the present time. I wish they would come out with a super vic. From all my research with these heads they make great torque across the whole curve, have reversion problems at .700" lift and are intake limited at about 6400-6800 rpm. Take a look at all the motors at present they table top at the mid 6000 rpms. They are thin castings as most GM heads are. Remember they were a truck head first. The new GM high tech dynos a 10 camaro with a TVS blower look at the curves fom 2000-6500 never less then 400 lb ft, the HP curve flattens out at 6000. That is bad *** for a stock car with a blower only. My built 383 didn't make that kind of power.
11-15-2009, 09:32 PM
#26
Also the stock 2.16" intake valve on the L92 head puts the valve very close to the cylinder wall. That is one of the reasons they work so much better on the LS3 (4.065" bore) than the LS2 (4.00" bore). Now increase the valve size to 2.20" and you are even closer. For the bigger 2.20" valve to work well it would need to be relocated closer to the center of the chamber. I'd like to see a full aftermarket LS3 casting that does just that, and has a smooth port with no bumps, adequate spring seat thickness, and 3/4" deck.
12-30-2009, 06:20 AM
#27
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prostock heads do this they use a formula for bore to intake valve size and then move the intake away from the wall as close to centre as possible and then move the ex valve against the wall, doing this increases intake efficiency and no loss from the ex, which can be gained back from more ex duration.
