AJPE Stage IV 481-X Cylinder Head
The Stage IV 481-X cylinder head is the lightest, most advanced 481-X cylinder head AJPE has made to date. An entire re-design of top, bottom, and ends of the cylinder head allows for five additional rocker stand fasteners for maximum rocker assembly stiffness and a reduction of over 5 pounds per cylinder head. This is the most rugged and advanced 481-X cylinder head available…period.
Standard Features Include:
- 73cc Chamber volume
- 2.450” Intake Valve (11/32 stem diameter)
- 1.920” Exhaust Valve (11/32 stem diameter)
- 50° Intake and Exhaust Seat Angles for improved seat life over 55° seats.
- Accepts .500 diameter intake pushrod and .565 diameter exhaust pushrod
- Copper alloy Intake and Exhaust seat material.
- Steel Valve Guides with Bronze liners.
- O-Ringed Intake ports for optimum seal and ease of assembly.
- Decks machined for AJPE designed Jr Hoops. @ +.018 protrusion above deck.
- Bare cylinder head weight 36.6 lbs. each
- Over 5 lbs. per head lighter than Stage 1, 2 or 3)
- Accepts 1.670 triple springs. (2.200 installed height with +.100 retainer)
- ½” head studs with steel hat washers installed.
- Accepts AJPE Stage I and II Header flanges, and Intake manifolds. (Stage I & II intake manifolds require modification to fit on Stage 4 head)
- All head studs are accessible from the top of the cylinder head. No inner head studs to deal with.
- Manifold can remain in place when removing cylinder heads from engine for ease of service.
- Machined to accept 14mm x .750 reach, “Gasket style” 13/16 hex spark plugs.
- 4.500 minimum bore diameter
- High Strength, Made in the USA 6061-T651 Aluminum Billet material.
- 100% CNC Ported for AJPE Accuracy, Performance & Consistency.
- Supplied completely finished ready to assemble out of the box.
***Requires AJPE Stage IV Rocker Stand and Valve Cover***
|
.900 |
.800 |
.700 |
.600 |
.500 |
.400 |
.300 |
.200 |
|
|
2.450 Intake Valve
551cc 4.500 Bore (#08 program) |
497 |
477 |
458 |
427 |
374 |
308 |
229 |
147 |
|
1.900 Exhaust Valve
198cc 4.500 Bore(#08 program)
|
347 |
334 |
315 |
292 |
259 |
219 |
178 |
131 |
All flow tests performed on Super Flow 1020 @ 28”, Exhaust tested w/ 2.500” od. pipe.
01B-004-08-JH 481-X Stage IV Billet Cylinder Heads, 50° Valve seats. Program #09. Bare, CNC ported ready to assemble, with Jr Hoops @ .018 out. (without Girdle Plates) (pair)