grumpyvette Posted July 1, 2004 Share Posted July 1, 2004 25534431 Vortec Bow-Tie Large Port Cylinder Head, Complete GM Performance Parts' latest and most powerful iron cylinder head with "Large Port" for Street or Racing. This Vortec design Special Performance cast iron cylinder head features revised intake and exhaust ports and includes 2.00" hollow stem intake valve P/N 12555331 and 1.55" sodium filled exhaust valves P/N 12551313. The deck surface is .450" with 65 cc combustion chambers, 206 cc intake and 77 cc exhaust ports. All Vortec intake ports are taller and narrower than early model Chevrolet heads. The valve cover mounting holes are for both early model flange and late model center. This head also includes intake manifold mounting holes for both early model 6 bolt main and late model 4 bolt Vortec design. The head has screw in rocker studs P/N 12552126, large valve spring pocket machining, and will accept up to .530" lift camshafts without modifications. Heads are identified with the Bow-Tie logo on the exterior of the head below exhaust flange and Vortec logo on top of intake port area. They also feature GM logo cast into bottom of intake ports. Includes valve spring P/N 12551483, valve seal P/N 10212810, and spring cap P/N 10212808. Technical Note: You must use a raised runner design intake mainifold P/N 10051103 (6 bolt mounting), or Vortec design 12366573, 12496820, 12496821, 12496822, and 12499371 (4 bolt mounting) with this head. You can use production Vortec intake gaskets P/N 12529094 (torque spec. 11 ft-lb/ 15Nm) for mounting Vortec design heads or use P/N 12497760 (torque spec. 30 ft-lb) with conventional material when using on early model raised runner or Vortec design intake manifolds, this gasket has both 6 bolt and 4 bolt Vortec attaching holes. Head casting P/N 25534371C. Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 1, 2004 Share Posted July 1, 2004 Pretty interesting. Any flow numbers or dyno comparisons with other heads yet? Quote Link to comment Share on other sites More sharing options...
383 240z Posted July 2, 2004 Share Posted July 2, 2004 Has anybody been able to source these from their dealer yet? Mine has the part number and pricing plan but no idea on an expected delevery date. And my birthday is comming up soon would be a nice gift to my self!! Keith Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted July 3, 2004 Share Posted July 3, 2004 I'm like Pete...anxiously awaiting the Airflow Numbers? Kevin, (Yea, Still an Inliner) Quote Link to comment Share on other sites More sharing options...
383 240z Posted July 7, 2004 Share Posted July 7, 2004 Just got off the phone with GM parts depot. those heads are 650 each retail 550 each wholesale. Keith Quote Link to comment Share on other sites More sharing options...
ToplessZ Posted July 8, 2004 Share Posted July 8, 2004 Man for that pile I could have a set of afr's now these may be good but not that good. Yipes. The old style vortecs have the bang for the buck these just have the bang for a lot of bucks. Everyone provides the latter. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted July 8, 2004 Share Posted July 8, 2004 I think the price is too pricey. GM probably made the heads for the racing classes that "Must Use Factory Cast Iron" heads...if there is even such a class. Too pricey for my pocket. For that price if I had my rathers, I would definately go with aluminum AFR's. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
383 240z Posted July 9, 2004 Share Posted July 9, 2004 I agree, evan with my discount I'll be staying with the AFR's plus I dont need a new EFI manifold if I stay away from the vortec style more cost savings!! Keith Quote Link to comment Share on other sites More sharing options...
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