Swirl port SBC heads
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==Overview== | ==Overview== | ||
| − | + | Swirl port SBC heads are often overlooked for any kind of performance use. This page will weigh the pros and cons of using them in a "street performance" application. | |
| − | Swirl port SBC heads are often overlooked for any | + | |
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| − | This page will weigh the pros and cons of using them in a "street performance" application. | + | |
==History== | ==History== | ||
| + | The SBC swirl port heads came to be in about 1987. | ||
==Casting numbers and ID== | ==Casting numbers and ID== | ||
| + | The 1987-up 5.7L TBI truck engines (also some marine engines) used c/n 14102191. Casting number 14102193 heads were also used on 1987-up truck engines and is also used on the 305 RPO LO3 engine. | ||
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| + | Both heads use center bolt valve covers. | ||
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| + | *191 have 76cc combustion chambers | ||
| + | *193 have 64cc combustion chambers | ||
==Design limitations== | ==Design limitations== | ||
| + | Its not that Swirlies outflow Vortec, its that they burn better and require less timing, generating more net torque. Less total timing = less negative work on the crankshaft as cylinder pressure is building. Up to 4,500 rpm many other heads cannot touch them. Where Vortecs like up to 12-16* of advance right off idle and as much as 32-34* total at high rpm, the Swirlies run best with only 4-6* of timing off-idle and 26-30* at high rpm. | ||
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| + | ===TBI swirl-inducing vane=== | ||
| + | [[File:Tbi swirl port vane1.jpg|thumb|left|350px|TBI swirl port vane (arrow)]][[File:Used 193-1.jpg|thumb|left|550px|TBI swirl port vane, paired combustion chambers]] | ||
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| + | ===L30 5.0L Vortec head=== | ||
| + | Some info and photos of the L30 5L Vortec head at [http://www.nastyz28.com/forum/showthread.php?t=56505&page=32 post 478]. | ||
| + | {| | ||
| + | |[[file:305_VORTEC_SWIRL_RAMP_CN_059.jpg|thumb|220px|center|305 Vortec L30 casting number 12558059]] | ||
| + | |[[File:305 VORTEC CHAMBER CN 059.jpg|thumb|500px|center|305 Vortec L30 casting number 12558059 chamber]] | ||
| + | |[[File:L31 305 VORTEC HEAD CASTING ID.jpg|500px|thumb|center|305 Vortec L30 casting ID]] | ||
| + | |} | ||
==Modifications and porting== | ==Modifications and porting== | ||
| + | *[http://www.youtube.com/watch?v=QMkCV1s5BQ8 Video] showing port work on a c/n 193 swirl port head. | ||
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| + | ==Resources== | ||
| + | *[http://www.mortec.com/castnum.htm SBC Heads casting numbers] by Mortec | ||
| + | *[http://outintheshop.com/faq/casting/castings2.html SBC head casting number go-to site] | ||
[[Category:Engine]] | [[Category:Engine]] | ||
| + | [[Category:GM]] | ||
| + | [[Category:Cylinder head]] | ||
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