SB Chevrolet Complete Small Port Vortec Bow-Tie Cylinder Head

Chevrolet Performance 25534421 | SB Chevrolet Complete Small Port Vortec Bow-Tie Cylinder Head
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SDPC Part Number: 25534421
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GM Performance Parts’ latest and most powerful iron cylinder head for Street or Racing. This Vortec design Special Performance cast iron cylinder head features revised intake and exhaust ports and is machined for 2.00" intake valve and 1.55" exhaust valves.

The deck surface is .450" and features 65 cc combustion chambers, 175 cc intake and 65 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 is machined for 3/8" screw in rocker studs(included), large valve spring pockets, 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.

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 25534351C.


Submitted by Guest (not verified) on

I loved the reg vortecs, im sure these are killer........a lil on the pricy side 4 an iron head

Submitted by Guest (not verified) on

I have a set on a street 350, their awsome.

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