225cc LS1 Mongoose Strip Head

The Ultimate Bolt-On Emission Legal Street/Strip Weapon

225cc CNC Ported w/parts 66cc ***Small Bore, Small chamber for 3.905" Stock Aluminum Bore blocks!***

For the maximum street/strip LS1/LS6 aluminum cylinder head AFR’s all new 225cc emission legal head E/O #D250-4 are hands down the best choice. Specifically designed for 1995 to present Gen-3 Chevy Corvettes, Camaros, and trucks. AFR’s LS1 head offers unmatched flow performance and features 2.080 intake and 1.600 exhaust valves with AFR’s iron ductile interlocking valve seats. The 225cc is ideal for normally aspirated 396C.I. to 427C.I. For a wild 346 ci the 225 is a good choice, however some low RPM loss of torque might occur. It is available with 62cc and 72cc combustion chambers. An affordable “as cast” version is also available. AFR’s LS1 is a direct bolt on, no special parts required. Structural features like Air Flow Research’s trademark 3/4” thick head deck, a must for blown and nitrous applications, reinforced rocker stud bosses and thick wall runners provide unparalled durability. An exclusive new modern combination chamber design with double quench pad area helps the LS1 generate huge low and mid lift airflow numbers. If you need a snake charmer for that pesky neighborhood “Cobra Mustang” look no further!

Note on bore sizes: AFR offers both a large bore and a small bore model 225 AFR cylinder head. The large bore (for the most part 'standard') AFR LS1 cylinder head is designed for a 4.0"+ cylinder bore, part number 1610. The small bore is PN: 1660 and is designed for the stock 3.902-3.905 aluminum block, it is essentially a LS1 205 chamber on a 225 cylinder head. Using a large bore cylinder head on a small bore engine can be done, but it is recommended to use the small bore cylinder heads.

Note on chamber sizes: AFR does not offer a small chamber Ls1 225 in any other configuration than the small bore. They offer the large chamber, large bore cylinder head that can be milled to a smaller chamber size if needed.

Note: Hydraulic roller cams in "LS" Gen III engines typically experience valve float at 6600-6800 RPM's. If your plan on running over .600 gross valve lift and/or 6600 RPM, AFR suggest you upgrade your springs to AFR part #8019. Our upgrade spring has higher seat and open pressures (145/390+) to better reduce the risk of valve float in more aggressive applications. AFR also recomends the use of Comp "R" lifters in conjunction with our 8019 spring upgrade.

Please note: AFR Ls1 bead locks and standard aftermarket bead locks are not interchangable. GM's standard bead lock radius and depth are different.

Basic Package Components

100% CNC Ported Combustion Chambers
100% CNC Ported Exhaust Ports
100% CNC Ported Intake Ports
3-angle Raduised Valve Job
Intake Valve, 2.080” standard length #7208
Exhaust Valve, 1.600” standard length #7228
1.290” O.D. Dual Hydraulic Valve Spring, 135 lbs. on seat, .600” maximum lift (upgrades available) #8017
7º 1.250 Titanium Retainers #8512
7º Valve Locks #9007
Valve Seals #6612
Spring Cup #8042
Intake Valve Seats #9059
Exhaust Valve Seats #9069
Bronze Valve Guides #9051

Specifications, Features, and Supporting Components

Head Torque 11MM ARP 70 FT lbs w/ Moly 8mm 23 FT lbs w/ Moly
Exhaust Port Gasket GM#12558573/ Fel-Pro #1440 AFR#6859
Intake Port Volume (as cast) 220cc
Intake Valve Size 2.080
Exhaust Port Volume (as cast) 78cc
Head Gasket GM#12498543 or 12498544, Fel-Pro#1041, AFR#6847 Cometic AFR #6846
Head Bolts & Studs Standard ARP, AFR #6330, #6331 & #6332
Head Bolt Washers Standard ARP, AFR #6328 & #6329
Jesel or TD Shaft Mount
Suggested Manifold LS6, FAST or TPIS
Accessory Holes Are Pre Drilled
Spark Plug Starting Range AC 41-974 Platinum
Combustion Chambers 66cc or 76cc
Spring Pocket 1.450 O.D can be machined to 1.550 O.D.
Valve Spacing Stock
Rocker Arms Location Stock
Valve Angle Stock
Angle Mill (milling available) .008” per cc
Flat Mill (milling available) .006” per cc

Note: Milling head deck will affect flow numbers