IM LOOKING FOR INFO ON A L98 BUILD UP I WANT TO PUT L31 VORTEC HEADS ON IT
I NEED ANY INFO GOOD OR BAD THIS IS WHAT IVE COME UP WITH
IVE HEARD THAT MAX LIFT STOCK IS .475 AND THAT THE HEADS BOTTOM OUT ON THE GUIDE AT .500 THESE HEADS FLOW ABOUT 215CFM@.400 LIFT THEN GO FLAT
THIS SEEMS A LITTLE SMALL
MOST OF THE MAJOR CAM MAKERS SPEC ROLLER CAMS FOR THESE ENGINES AT AROUND .480-.520 LIFT? BUT THESE HEADS FLOW GREAT BETWEN .200-.450
I ALSO WANTED TO USE 1.6 ROCKERS WITCH SEEMS OUT OF THE QUESTION! DO THESE MOTORS (OR HEADS) RESPOND TO LIFT OR DURATION? CAM HELP WOULD BE APPERECIATED
ANYWAY I HAVE A JET CHIP, SLP RUNNERS, AIR FOIL, DUAL CAT EXHAUST, FLOWMASTER AMERICAN THUNDER EXHAUST ,HV FUEL PUMP,REGULATOR ,STOCK LARGE BORE EXHAUST MANAFOLD WORKED 700R4 3.08 REAR,CAR WAS ORIGINALY AN LG4 BUT I PUT A HOWELL HARNESS IN IT
THE INTAKE WILL BE FROM SCOGGEN CHEVY.IM LOOKING TO PULL ABOUT 300-325HP AT ABOUT4500 RPM AND REV TO 5500 DOES THIS SOUND UNREASONABLE?
ANY HELP WOULD BE APPERECIATED AND NO MY KEYBOARD IS NOT BROKE .THANKS SCOTT

 

Your keyboard is broken

 

WOW THATS ONE LONG SENTENCE AND IN ALL CAPS NO LESS THATS KINDA HARD TO READ

But seriously, the Vortec heads are pretty good. Chevy Hi Performance magazine did some dyno and flowbench testing on these heads a year or so ago and the results were impressive.

 

Some more info for ya:

GM High Tech Performance magazine Sept 2000 issue did a big flowbench comparison of heads including the Vortec. The raw intake CFM does stall between .400 (121.53cfm) and .500 (211.37cfm) but intake doesn't (151.05cfm@0.400, 159.00cfm@0.500). The swirl rate goes up bigtime though...2400rpm@.400 and 2471rpm@.500.

For an upgraded Vortec head including screw-in rocker studs, better valves, and springs good to 0.550" lift check out Wheeler Motorsports (www.wheelermotorsports.net). Still cheap @ ~$300 each and ready to go out of the box.

 

I am thinking along the lines of a similar setup. Generally I think these heads respond to duration and a lean fuel mixture(hot). I think this setup should be good for over 300 HP and a well put together 3rd gen should be able to pull flat 13s or high 12s. I will hopefully have all this done by next year and we'll see what happens. As for your setup, I'd like to keep in touch with your progress, maybe post here every so often.