Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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I was looking at these heads and noticed that they said that they accept the 6 bolt intakes from the earlier engines with this note, 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.
Would these heads work with a stock Holley StealthRam and would they be a decent upgrade on a 305 TPI motor?
No. The bolt angles are different, and the ports are raised. You can use any heads except for raised runner style like the fast burn heads. The intake has the four centerholes elongated for either style bolt pattern. But you will need to get beveled washers or the Weiand #90748 bolt kit if using the 1987-up design.
