SBC cylinder head identification
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==Casting numbers== | ==Casting numbers== | ||
| − | Located under the valve covers, the casting number is the best way to ID a SBC head. The number along with the date code can be used to pinpoint the heads original application fairly closely. Valve sizes (1.94" intake x 1.5" exhaust or 2.02" intake x 1.60" exhaust) and whether or not screw-in studs and | + | Located under the valve covers, the casting number is the best way to ID a SBC head. The number along with the date code can be used to pinpoint the heads original application fairly closely. Valve sizes (1.94" intake x 1.5" exhaust or 2.02" intake x 1.60" exhaust) and whether or not screw-in studs and guideplates are in place can further ID them. Be aware that screw-in studs/guideplates were not used on all, or even most, large valve SBC performance heads from the factory, and if present, they could very well have been added previously. |
Click [[Cylinder head identification#Resources|'''HERE''']] for sites with information on casting numbers. | Click [[Cylinder head identification#Resources|'''HERE''']] for sites with information on casting numbers. | ||
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===Casting number "462" fuelie heads=== | ===Casting number "462" fuelie heads=== | ||
'''462''' is the most-used SBC head casting number out there- at least six different SBC cylinder head casting numbers end in 462, according to 'the books': | '''462''' is the most-used SBC head casting number out there- at least six different SBC cylinder head casting numbers end in 462, according to 'the books': | ||
| − | + | * 3990462 | |
| − | + | * 3767462 | |
| − | + | * 3782462 | |
| − | + | * 3814462 | |
| − | + | * 3890462 | |
| − | + | * 3891462 | |
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So both the c/n 906 and c/n 062 heads have virtually the exact same performance potential. In fact there are instances like for marine use where the hardened exhaust seat insert is actually preferred over the induction hardened seat. | So both the c/n 906 and c/n 062 heads have virtually the exact same performance potential. In fact there are instances like for marine use where the hardened exhaust seat insert is actually preferred over the induction hardened seat. | ||
{| | {| | ||
| − | |[[File:Induction hardened seat vortec.jpg|thumb|center|400px|Induction hardened Vortec exhaust seat, note the | + | |[[File:Induction hardened seat vortec.jpg|thumb|center|400px|Induction hardened Vortec exhaust seat, note the discolored area around seat]] |
|[[File:Hard insert seat vortec 906.jpg|thumb|center|400px|Hardened exhaust seat insert in a c/n 906 Vortec head]] | |[[File:Hard insert seat vortec 906.jpg|thumb|center|400px|Hardened exhaust seat insert in a c/n 906 Vortec head]] | ||
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*'''A-''' Rectangle c/n 460, 1955 & up 265/283, 8:1 CR, 1.72" x 1.50" valves. | *'''A-''' Rectangle c/n 460, 1955 & up 265/283, 8:1 CR, 1.72" x 1.50" valves. | ||
| − | *'''B-''' Narrow triangle over rectangle c/n 520, 896, 1958 and up 283 | + | *'''B-''' Narrow triangle over rectangle c/n 520, 896, 1958 and up 283 Power Pak and 1957-'60 FI. 9.25:1 CR, 1.72" x 1.50" valves, 59cc nominal chamber volume. Could be used on a 305 but no accessory holes and has unhardened exhaust seats. |
*'''C-''' Vertical bar over rectangle c/n 997, 1957 Corvette 270 HP, 9.5:1 CR, chamber similar to Power Pak but with sharp corners in plug area. | *'''C-''' Vertical bar over rectangle c/n 997, 1957 Corvette 270 HP, 9.5:1 CR, chamber similar to Power Pak but with sharp corners in plug area. | ||
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*'''I-''' Large triangle over rectangle (“crown”) c/n 882. Large chamber (76 cc nominal), hardened exhaust valve seats, compromised intake port (1971-'76 350/400 cid). One of the most common smog heads, performance use is limited. | *'''I-''' Large triangle over rectangle (“crown”) c/n 882. Large chamber (76 cc nominal), hardened exhaust valve seats, compromised intake port (1971-'76 350/400 cid). One of the most common smog heads, performance use is limited. | ||
| − | *'''J-''' No casting identifier c/n 113, 1986-'90 Corvette and GMPP 350 HO, aluminum with no exhaust heat cross over, 58cc chamber, 1.94" x 1.50" valves, centerbolt valve covers, good 305 or light performance 350 street head especially if ported, 1988-on have raised D-shaped exhaust port, 3/8" screw-in studs and | + | *'''J-''' No casting identifier c/n 113, 1986-'90 Corvette and GMPP 350 HO, aluminum with no exhaust heat cross over, 58cc chamber, 1.94" x 1.50" valves, centerbolt valve covers, good 305 or light performance 350 street head especially if ported, 1988-on have raised D-shaped exhaust port, 3/8" screw-in studs and guideplates. |
*'''K-''' 3 right-facing “stairs” (“bench” on intake runner) c/n 487. 1971-'76 76 cc, said by many to be the best large chamber head. 1.94" x 1.50" or 2.02" x 1.60" valves were used, big valve heads machined for screw-in studs and guideplates. | *'''K-''' 3 right-facing “stairs” (“bench” on intake runner) c/n 487. 1971-'76 76 cc, said by many to be the best large chamber head. 1.94" x 1.50" or 2.02" x 1.60" valves were used, big valve heads machined for screw-in studs and guideplates. | ||
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==SBC heads to avoid== | ==SBC heads to avoid== | ||
| − | *The c/n 462624 is said to be very prone to cracking. Even though they can be found fitted with 2.02" x 1.60" valves and screw in studs/ | + | *The c/n 462624 is said to be very prone to cracking. Even though they can be found fitted with 2.02" x 1.60" valves and screw in studs/guideplates from the factory, they still are not a good choice for serious performance use. |
| − | *1971-up heads with casting numbers 882, 993, 487, 336 (and others) can have 3/8" exhaust stems as well as 1.72" intake valves. Heavy 20-30 Series truck uses these, mainly. Both small 1.72" intake and 3/8" stem exhaust valves may be found on c/n | + | *1971-up heads with casting numbers 882, 993, 487, 336 (and others) can have 3/8" exhaust stems as well as 1.72" intake valves. Heavy 20-30 Series truck uses these, mainly. Both small 1.72" intake and 3/8" stem exhaust valves may be found on c/n 261, 624. Also 1987-'95 center bolt valve cover-type head c/n 14102191 can also have the 3/8" exhaust valve stem. |
| − | *Usually swirl port TBI SBC heads are not used in high performance applications because they run out of breath earlier than the RPM most performance camshafts need to make peak power. Some casting numbers for them are 187, 191, 193. Similar to the [http://www.crankshaftcoalition.com/wiki/Swirl_port_SBC_heads swirl port heads], but without the swirl-inducing vane are c/n | + | *Usually swirl port TBI SBC heads are not used in high performance applications because they run out of breath earlier than the RPM most performance camshafts need to make peak power. Some casting numbers for them are 187, 191, 193. Similar to the [http://www.crankshaftcoalition.com/wiki/Swirl_port_SBC_heads swirl port heads], but without the swirl-inducing vane are c/n 14011083 and 14096217. |
==Current head casting/part numbers, specs== | ==Current head casting/part numbers, specs== | ||
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