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HEAD BUILD KITS
Speedmaster offers most of our heads as bare castings, or professionally assembled. When we assemble heads, extra time is taken to set them up for YOUR application. All you have to do is choose the head casting you want and the type of cam you want the springs to work with.
HEAD BUILD KIT OPTIONS:
TYPE HEAD BUILD KIT CLOSED SEAT PRESSURE OPEN SEAT PRESSURE MAX. LIFT Hydraulic Flat Tappet Solid Flat Tappet Hydraulic Roller Solid Roller Race Solid Roller
HBK21 HBK22 HBK23 HBK24 HBK25
110 LBS 125 LBS 145 LBS 210 LBS 300 LBS
300 LBS 320 LBS 360 LBS 450 LBS 700 LBS
. 550”. 580”. 580”. 650”. 800”
INTAKE GASKETS
The SM3021 heads work well with our SM3289 rectangle port gaskets. The SM3021-396 heads require our SM3290 oval port gaskets. If you prefer Felpro gaskets, the SM3021 heads take a 1275 or 1275-5 gasket, depending on the thickness you require.
The CNC-ported heads( SM3028-125) are matched to the Felpro 1275 & 1275-5 gaskets.
HEAD GASKETS
Due to the wide combustion chamber needed to fit around the large 2.250 / 1.880” valves, we recommend our SM5211 MLS head gaskets. These gaskets are. 041” thick, and fit bore sizes as large as 4.540” on all Mark IV and VI blocks, as well as aftermarket blocks. Felpro 1017 gaskets will also work with these head / block combos. To install our BBC heads on Mark V blocks, you will need to use our SM5233L and SM5233R Elite Series MLS head gaskets. Alternatively, you can use Victor Reinz # 4918( R) & # 4923( L) head gaskets on Mark V blocks with our heads.
HEAD BOLTS / STUDS
Due to the raised(+. 625”) exhaust port location on our heads, +. 100” longer bolts / studs are needed next to each port. Use our pn # SM2452-6100 head stud Kit. ARP # 135-3703 12pt. Head bolts, and # 235-4303 Head studs work too. If you already have a standard BBC head stud kit and are just looking for the 8 +. 100” studs, use our pn # SM2452-6100-8 or ARP # 235-4306. These heads should be torqued to 65ft. lbs. using high pressure moly lube or 70ft. lbs. using 30wt. oil.
Please consult your fastener manufacturer for their specific recommended torque values.
EXHAUST GASKETS
Our BBC heads utilize a 1.88” x 1.88” square exhaust port. This exhaust port requires specific gaskets. Our pn # SM5202 gaskets are made of re-useable copper, or if you prefer paper, use our pn # SM5123. Felpro also offers gaskets that work with our heads as # 1410.
SPARK PLUGS
Our heads require the use of 14mm. x 3 / 4” reach 5 / 8” hex gasket seat sparkplugs. Some recommended plugs are; NGK BCPR6ES or R5671A-7, Champion RC12YC, Autolite AR3923 or AR3924. Remember these are for mild street engines. Higher compression or boost requires colder sparkplugs!
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