Gm Sbc Heads Phase 2 #10134392 on 2040-parts.com

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10134392 Phase 2 Cast Iron Bow Tie Head The Phase 2 Bow Tie cylinder head (casting P/N 14011034) has the highest performance potential of any cast iron Chevrolet head. It is intended for off-highway applications only. Although the Phase 2 cast iron Bow Tie cylinder head has the same casting number (14011034) as the Phase 1 head it replaced, there are several significant differences between these two heavy-duty cylinder heads. The Phase 2 cast iron Bow Tie head can be identified by its redesigned outer water jacket wall with a machined bar between the exhaust manifold flanges. (Phase 1 castings have a raised parting line between the exhaust manifold flanges.) The area around the tapped water temperature sensor hole is also machined flat on the Phase 2 head. The Phase 2 Bow Tie head has a revised combustion chamber design with a true volume of 64cc's. The quench areas beneath the spark plugs are filled to increase compression in competition engines. The intake valve seats are machined for 2.02" diameter valves; the induction hardened exhaust valve seats are finished for 1.60" diameter valves. The intake and exhaust ports are identical in Phase 1 and Phase 2 cast iron Bow Tie heads. The 184cc intake runners will satisfy the airflow requirements of most competition engines while enhancing throttle response and mid-range torque. In unmodified form, the Phase 2 Bow Tie head will flow more air than any production cast iron small-block head. Extra-thick wall sections allow the ports to be enlarged to increase their flow capacity. The manifold heat riser passages are deleted in Phase 2 Bow Tie heads to produce a cool, dense intake charge. Technical Notes: The valve spring pockets in cast iron Bow Tie heads are machined for up to 1.50" diameter competition valve springs. The rocker stud bosses are tapped for screw-in studs; studs and pushrod guideplates are not included. Use GM Performance Parts studs P/N 3973416 (3/8") or P/N 3921912 (7/16") and hardened pushrod guideplates P/N 3973418. Use 5/8" hex-head spark plugs with tapered seats and 3/8" reach. A bare casting weighs approximately 42 pounds. Valve seats are heat-treated. that would be for the phase 2 bowtie head. the newer, at least i think it is newer casting, bowtie phase 3 head are this here: 12480034 Phase 3 Cast Iron Bowtie Head Extra-thick walls for porting Machined for 2.02/1.60 valves Exhaust seats are induction hardened Valve spring seat is machined for 1.50 competition springs 184cc intake runner 64cc combustion chamber No heat riser Angled spark plugs (5/8 hex, 3/8 reach, tapered plugs) Requires early model intake manifolds Valve spring seat is machined for 1.50 competition springs Use P/N 12495497 screw-in studs for 3/8 rocker arms Use P/N 3921912 screw-in studs for 7/16 rocker arms Use P/N 3973418 guideplates for hardened pushrods