This all new 23° fast burn Vortec cylinder head has the highest performance potential of any 23° SB head developed by GM using flat top pistons. This head is a bolt-on 30 hp increase when used on GM's ZZ4 crate engine. 62cc fast burn combustion chambers produce higher cylinder pressures by burning more of the available fuel before the piston starts its power stroke downward. Heads and rocker rails are CNC machined to exacting tolerances, thus eliminating the need for ''blue-printing'' of machined tolerances. ''D'' shaped 78cc exhaust, and 210cc intake port and runners require no additional porting, but is recommended for all out racing. Fits all, 1958 to present, 283-400ci SB V-8 engines with conventional water flow design; but cannot be used on any LT1, LT4 or LS1 engine with reverse water flow. Comes completely assembled with valves, springs, retainers, and 3/8'' rocker studs. Requires the use of self-aligning rocker arms.


Material: Aluminum
Intake Runner Volume: 210cc
Combustion Chamber Volume: 62cc
Valve Diameter: 2.00'' Int./ 1.55'' Exh.
Spark Plugs: Angled

These fully assembled, CNC-machined aluminum Fast Burn cylinder heads from GM Performance are designed for 1958-2000 283-400 c.i.d. Chevy V8s. They quickly and completely burn the air/fuel mixture, ensuring higher cylinder pressure and more power. No additional porting is required--GM Performance Parts' cast-ported technology gives these heads maximum performance right out of the box. They're drilled and tapped for Vortec and raised port manifolds, they accept flange-mount or centerbolt-style valve covers, and will support in excess of 500 HP.

12464298
Aluminum Fast Burn Cylinder Head Assembly
CNC-machined aluminum performance head
Completely assembled with 2.00/1.55 valves
210cc intake port, roof raised .240
78cc D-shaped exhaust ports, raised .200, requires Fel-Pro' gasket #1470 (may require minor trimming)
62cc combustion chamber, .400 thick deck (can be milled safely .060)
No heat riser
Angled spark plugs (5/8 hex, 3/4 reach, tapered plugs)
1.48 Valve spring seat diameter
Use head gaskets with stainless steel fire rings
Raised, machined rocker rails
0.530 max valve lift (without modifications)
Screw-in studs, (3/8 top, 7/16 bottom)
Dual bolt patterns for perimeter bolt and center-bolt valve covers
Dual bolt patterns for both Vortec and early model intake manifolds
Use production intake gasket P/N 12529094 for Vortec intakes or dual bolt pattern intake gasket P/N 12497760 for either early model or Vortec design manifolds (Fel-Pro' #1289 and #1207 may be used)

This head is assembled with the following components:
12555331 Intake Valves
10212808 Valve Spring Retainers
12551313 Exhaust Valves
10212810 Valve Stem Seals
12551483 Valve Springs
10212809 Valve Spring Shims
12552126 3/8 Rocker Studs
24503856 Valve Locks

"Part # 12555331
2.00" Valve Size, 11/32" Stem Size. Stock replacement valve used in the 1996 LT4 engine, and in our CT350/400, Fast Burn 385 & ZZ383/425 also in LT4 and Fast Burn heads."

"Part # 12551313
1.55" Valve Size, 11/32" Stem Size. Stock replacement valve used in the 1996 LT4 engine, and in our CT350/400, Fast Burn 385 & ZZ383/425 also in LT4 and Fast Burn heads."