SBC cylinder head identification
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| + | =Basics of cylinder head identification= | ||
| + | ==Chevrolet== | ||
| + | ===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 guide plates are in place can further ID them. Be aware that screw-in studs/guide plates 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. | ||
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| + | ===Casting identifiers=== | ||
| + | Through the years, small block Chevy heads have been ID'd by the head's end casting shapes. | ||
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| + | ===="Fuelie" heads==== | ||
| + | The most recognized end casting identifier of the SBC heads is the "fuelie", "double hump", or "camel hump". It got the name fuelie from the fact that it was used on the fuel injected Corvette engines. Double hump and camel hump is from the physical shape of the casting. The fuelie heads was used from the 1960's to the 1970's on the high performance optional engines up to and including the 375 HP fuel injected L-84 327 cid engine, and the 365 HP L-79 4-barrel engine of 1964, and the bad-to-the-bone LT-1 engine, to name just three. | ||
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| + | '''462''' is the most-used SBC head casting number out there- at least six different c/n end in 462, according to 'the books': | ||
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| + | • 3990462 | ||
| + | • 3767462 | ||
| + | • 3782462 | ||
| + | • 3814462 | ||
| + | • 3890462 | ||
| + | • 3891462 | ||
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| + | ====Vortec L30 5.0L heads==== | ||
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| + | ====Vortec L31 5.7L heads==== | ||
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| + | The casting numbers are '''12559062''' and '''10239906'''. | ||
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| + | [[File:062_VORTEC_END_ID_001.jpg|left|frame|Casting number 12558062 head has 3 small humps, aka "sawtooth" on the end of the head.]][[File:906 VORTEC END ID.jpg|right|frame|Casting number 10239906 head has one large single hump on the end of the head.]] | ||
| + | <br style="clear:both"/> | ||
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| + | <gallery> | ||
| + | File:062_VORTEC_END_ID_001.jpg|Casting number 12558062 head has 3 small humps, aka "sawtooth" on the end of the head. | ||
| + | File:906 VORTEC END ID.jpg|Casting number 10239906 head has one large single hump on the end of the head. | ||
| + | </gallery> | ||
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| + | ====Diagram of some common head ID castings==== | ||
| + | [[File:Sbc head casting id.jpg]] | ||
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| + | *'''A-''' Rectangle c/n 460, 1955 & up 265/283, 8:1 CR, 1.72" x 1.50" valves. | ||
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| + | *'''B-''' Narrow triangle over rectangle c/n 520, 896, 1958 and up 283 PowerPak and 1957-'60 Fuel Injection. 9.25:1 CR, 1.72" x 1.50" valves, 59cc nominal chamber volume. Could be a replacement for 305 but no accessory bosses and unhardened exhaust seats. | ||
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| + | *'''C-''' Vertical bar over rectangle c/n 997, 1957 Corvette 270 HP, 9.5:1 CR, chamber similar to PowerPak but with sharp corners in plug shroud area. | ||
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| + | *'''D-''' 2 vertical bars over rectangle, c/n 997, 1956 Corvette 2X4-bbl 283; 1958 passenger car FI; chamber same as 1957 270 HP Corvette. | ||
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| + | *'''E''', '''F-''' Large “camel hump” c/n 291, 461, 461X, 462. Original high performance or “fuelie” heads, chamber sizes are 62-64 cc nominal, came with both 1.94" x 1.50" or 2.02" x 1.60" valves, c/n 291 on 327 through 1968; c/n 291 have temp sender hole; 462 do not have sender hole. | ||
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| + | *'''G-''' Left-facing right triangle c/n 041, 1969-'70 350/300HP, accessory bolt holes, most have 1.94" x 1.50" valves | ||
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| + | *'''H-''' Small “camel hump” c/n 186, 492. Later high performance or “fuelie” heads, some c/n 186 (1969 and later) and all c/n 492 have accessory bolt holes. Either 1.94" x 1.50" or 2.02" x 1.60" valves, 64cc nominal chamber volume. 1970 LT-1/Z-28 use c/n 492. Available as p/n 3987376. | ||
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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. | ||
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| + | *'''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 guide plates. | ||
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| + | *'''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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| + | *'''L-''' Right-facing “bench” c/n 993. Common large chamber smog head, not a lightweight casting. Similar to c/n 487. Used on the SBC 400, so may have steam holes and 1.60" exhaust valves. Hardened exhaust seats. | ||
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| + | *'''M-''' One triangle c/n 882. Alternative marking for 882 (see '''I''' above). Hardened exhaust seats. | ||
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| + | *'''N-''' 2 triangles c/n 624. Late model lightweight casting version of c/n 882. Said to be crack prone. Used on Corvette and Camaro high performance engines with 2.02" x 1.60" valves. Hardened exhaust seats. | ||
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| + | *'''O-''' “Saddle” and vertical bar c/n 416. Late-model 305, conventional perimeter valve cover, intake port not restricted, lightweight, 57 cc nominal chamber volume. Hardened exhaust seats. | ||
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| + | *'''P-''' Double (Captain’s) bars c/n 193. Used on TBI equipped engines. Mid-1980- up style centerbolt valve cover. Has restrictive vane cast in intake port to induce swirl/turbulence. Not usually recommended for high RPM performance applications unless serious port work is done. Hardened exhaust seats. | ||
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| + | ====SBC heads to avoid==== | ||
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| + | The c/n 624 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/guide plates from the factory, they still might not be a good choice for serious performance use. | ||
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| + | 1971-up heads with casting numbers 882, 993, 487, 336 can have 3/8" exhaust stems as well as 1.72" intake valves. Heavy 20-30 Series truck use, mainly. Both small 1.72" intake and 3/8" stem exhaust valves may be found on c/n's 261, 624. Also 1987-'95 center bolt v-cover-type head # 14102191 can have the 3/8" exhaust valve. | ||
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| + | 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 heads, but without the swirl-inducing vane | ||
| + | are c/n's 14011083 and 14096217. | ||
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| + | ==AMC== | ||
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| + | ==Ford== | ||
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| + | ==Mopar== | ||
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==Specific procedures and links== | ==Specific procedures and links== | ||
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[[Category:Identification and decoding]] | [[Category:Identification and decoding]] | ||
[[Category:Engine]] | [[Category:Engine]] | ||
| + | [[Category:undeveloped articles]] | ||
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