Cadillac engine knowledge
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| 1976 || 500 || EFI || 215@3600 || 400@2000 || 4.300x4.304 || align="center" | 8.5-1 | | 1976 || 500 || EFI || 215@3600 || 400@2000 || 4.300x4.304 || align="center" | 8.5-1 | ||
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===Tune-up specifications=== | ===Tune-up specifications=== | ||
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| 1975-'76 || 500 || EFI || R45NSXgap@.060 || align="center" | HEI || align="center" | 12B || align="center" | 21B || align="center" | 600 | | 1975-'76 || 500 || EFI || R45NSXgap@.060 || align="center" | HEI || align="center" | 12B || align="center" | 21B || align="center" | 600 | ||
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===Fastener torque specifications=== | ===Fastener torque specifications=== | ||
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==Modifications and swapping== | ==Modifications and swapping== | ||
| − | + | [[File:Mts cad head.jpg|thumb|left|600px|MTS custom aluminum 76cc "FR" head, ~$3500/pair ca. 2012]] <br style="clear:both"/> | |
===Heads=== | ===Heads=== | ||
| − | The biggest gains in power output come | + | The biggest gains in power output come from aftermarket cylinder heads (see photo). Stock heads can also be ported for more power. MTS and others do this type of work. Pre-1974 heads are small chamber 76cc and are good for around 12-13 to 1 compression when a flat top piston is fitted. Race gas, alcohol or propane fuel must be used. |
| − | The 1974 and later open chamber heads have | + | The 1974 and later open chamber heads have 120cc chambers giving compression ratios of 7.5-9 to 1 depending on the piston used. |
Big gains can be made by adding larger valves. The valve sizes can be boosted to 2.19"/1.84" without worry of hitting the water jackets. The usual porting, valve unshrouding and minor bowl modifications will work, although the short-side radius should be left alone to avoid drastic differences in airflow. Roughly 20 hp can be gained by this work alone and most of that comes from the larger valves. | Big gains can be made by adding larger valves. The valve sizes can be boosted to 2.19"/1.84" without worry of hitting the water jackets. The usual porting, valve unshrouding and minor bowl modifications will work, although the short-side radius should be left alone to avoid drastic differences in airflow. Roughly 20 hp can be gained by this work alone and most of that comes from the larger valves. | ||
The 1977-'79 425 heads have 108cc chambers giving about 10:1 compression ratio depending on the piston used. The 425 heads have restricted air flow due to their port design making them the least desirable for modification. The head gasket is different as well. | The 1977-'79 425 heads have 108cc chambers giving about 10:1 compression ratio depending on the piston used. The 425 heads have restricted air flow due to their port design making them the least desirable for modification. The head gasket is different as well. | ||
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| + | ===Intake=== | ||
| + | The stock intakes used on the 472/500/425 engines leave a lot to be desired. They are a very low rise design, some are single plane, but not in a high performance sense. | ||
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| + | MTS, Edelbrock and others make aluminum aftermarket intakes that are better suited for high performance duty. | ||
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| + | [[File:Mts single plane intake cad.jpg|thumb||left|600px|MTS single plane aluminum intake manifold]] <br style="clear:both"/> | ||
===Block=== | ===Block=== | ||
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