Cadillac engine knowledge
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1968-'69 472: 1486238 | 1968-'69 472: 1486238 | ||
| − | 1970-'76 472 & 500: 1485200 | + | 1970-'76 472 & 500: 1485200 (1486200 was used on some 1974-'76 500 engines) |
1977-'79 425: 1609110 | 1977-'79 425: 1609110 | ||
| − | 1980-'85 368: 1615255 Carb 1620734 EFI | + | 1980-'85 368: 1615255 Carb; 1620734 EFI |
===Crank casting number=== | ===Crank casting number=== | ||
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(Stroke can be measured through spark plug hole if the engine will turn over.) | (Stroke can be measured through spark plug hole if the engine will turn over.) | ||
| − | 1968-'74 472, 1977-'79 425, 1980-'85 368: 4.060" (less than 4 1/8") | + | 1968-'74 472, 1977-'79 425, 1980-'85 368: 4.060" (less than 4-1/8") |
| − | 1970-'76 500: 4.300" (more than 4 1/4") | + | 1970-'76 500: 4.300" (more than 4-1/4") |
===Head casting number=== | ===Head casting number=== | ||
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1980-'85 368: 1615188, others unknown. The 4-6-8 head is substantially different than the regular head, and the rocker assemblies are not directly interchangeable. | 1980-'85 368: 1615188, others unknown. The 4-6-8 head is substantially different than the regular head, and the rocker assemblies are not directly interchangeable. | ||
| − | A fairly comprehensive 2 page PDF ID guide with pictures | + | A fairly comprehensive 2 page PDF ID guide with pictures (mostly on the 472/500 engines) can be found [http://www.cad500parts.com/tech/EngineIDPages.pdf HERE]. For a quick ID, on the second page there is a box shape shown on the rear of the 1977-later blocks to ID the smaller engines. Distinguishing a 1970-newer 472 from a 500 can only be done by crank number, stroke, or piston design, as all other parts are the same. |
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*'''TH400''' | *'''TH400''' | ||
| − | The basic 472 and the later 500 engines both use a Buick/Pontiac/Olds/Cadillac (BOPC) bell housing bolt pattern, so a TH400 automatic will bolt right up to the back of the block as long as the proper Cadillac flexplate and torque converter are used. The TH425 front-drive automatic transaxle also fits these engines as used in the Eldorado, although a special dual-sump oil pan and pickup are used with these transmissions due to the required half shaft clearance. Any RWD engine can be converted to FWD and vice versa if the proper oil pan and pickup are used, although two of the main cap bolts must be removed and swapped for studs with standoffs to mount the pickup bracket. Another good thing about these engines using a TH400 transmission is that a BOPC patterned case can be assembled with the Chevy 4x4 tailshaft and associated hardware for use in an off-road truck. The engine weight is approximately 600 pounds fully dressed and splits the difference between small and big block Chevy, so suspension modifications are not usually necessary. Transfer case choice for a 4x4 should be a NP205, as fitted to some mid/late | + | The basic 472 and the later 500 engines both use a Buick/Pontiac/Olds/Cadillac (BOPC) bell housing bolt pattern, so a TH400 automatic will bolt right up to the back of the block as long as the proper Cadillac flexplate and torque converter are used. The TH425 front-drive automatic transaxle also fits these engines as used in the Eldorado, although a special dual-sump oil pan and pickup are used with these transmissions due to the required half shaft clearance. Any RWD engine can be converted to FWD and vice versa if the proper oil pan and pickup are used, although two of the main cap bolts must be removed and swapped for studs with standoffs to mount the pickup bracket. Another good thing about these engines using a TH400 transmission is that a BOPC patterned case can be assembled with the Chevy 4x4 tailshaft and associated hardware for use in an off-road truck. The engine weight is approximately 600 pounds fully dressed and splits the difference between small and big block Chevy, so suspension modifications are not usually necessary. Transfer case choice for a 4x4 should be a NP205, as fitted to some mid/late 1970's Chevy 1 ton trucks. The NP205 is a strong gear-driven transfer case and holds up nicely to the big Caddy's torque output. |
*'''700R4/4L60/4L80E''' | *'''700R4/4L60/4L80E''' | ||
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===Oil pumps=== | ===Oil pumps=== | ||
There are different oil pumps for the big Cadillac engines. One faces forward from the block at a 45 degree angle downward. The next faces downward 45 degrees and points right toward the bottom of the crankshaft pulley. There is another, that has been described as pointing more outward than the first one described. These can all be interchanged, but make very sure to properly clean the oil pump and block mating surfaces and always use a new oil pump gasket. The correct gaskets are available from major gasket manufacturers, and should be about 0.005" thick. An oil pump gasket that is too thick will cause more oil to bypass the pump gears and allow more end play of those gears too, something you do not want. | There are different oil pumps for the big Cadillac engines. One faces forward from the block at a 45 degree angle downward. The next faces downward 45 degrees and points right toward the bottom of the crankshaft pulley. There is another, that has been described as pointing more outward than the first one described. These can all be interchanged, but make very sure to properly clean the oil pump and block mating surfaces and always use a new oil pump gasket. The correct gaskets are available from major gasket manufacturers, and should be about 0.005" thick. An oil pump gasket that is too thick will cause more oil to bypass the pump gears and allow more end play of those gears too, something you do not want. | ||
| + | |||
| + | The stock Cad oil pump spring can be shimmed using a Q-jet metering jet to boost oil pressure to about 50-60 psi. 10-12 psi per 1000 rpm is good. Make sure to prime the oiling system using an electric drill to spin the pump after you do this to check for proper operation of the pump and pressure bypass and to check the oil pressure psi. | ||
===Oil Pans=== | ===Oil Pans=== | ||
RWD pans used a front-sump pan and pickup. The Eldorado used a rear-sump setup. Later 425 and 368 engines used a mid-sump style. The latter two pans are what you would typically use for most engine swaps. | RWD pans used a front-sump pan and pickup. The Eldorado used a rear-sump setup. Later 425 and 368 engines used a mid-sump style. The latter two pans are what you would typically use for most engine swaps. | ||
| − | + | If possible, use the front sump oil pan design to eliminate the longer pickup; this will help keep the engine primed instead of using a thicker motor oil. | |
===Clearance issues=== | ===Clearance issues=== | ||
In cars the clearance problems are usually at the front crossmember, the driver side exhaust manifold, and possibly the HVAC airbox on the firewall. This can be modified with fiberglass or sheetmetal if necessary. Streetrods usually have sufficient room to drop the big Cad engine in. The fit is tight like with a big block Chevy, but the only change usually required will be in motor mount placement. Most all vehicles requiring a rear-sump oil pan and pickup can use the Eldorado pan and pickup tube, or a mid-sump pan and pickup as found on the smaller 368-425 Cadillac engines of 1977-'79 vintage. Stock exhaust manifolds may be used, or aftermarket block-hugger style headers can be sourced from Sanderson. In most cases where a big block Chevy header can be used, the Chevy flanges can be removed and Cad flanges can be made up quite easily. The primary tubes may need a bit of tweaking to line up with the ports with this method. Remember that the front and rear drive exhaust manifolds are different for the driver side. This may help in routing the exhaust if it is a tight fit on that side. | In cars the clearance problems are usually at the front crossmember, the driver side exhaust manifold, and possibly the HVAC airbox on the firewall. This can be modified with fiberglass or sheetmetal if necessary. Streetrods usually have sufficient room to drop the big Cad engine in. The fit is tight like with a big block Chevy, but the only change usually required will be in motor mount placement. Most all vehicles requiring a rear-sump oil pan and pickup can use the Eldorado pan and pickup tube, or a mid-sump pan and pickup as found on the smaller 368-425 Cadillac engines of 1977-'79 vintage. Stock exhaust manifolds may be used, or aftermarket block-hugger style headers can be sourced from Sanderson. In most cases where a big block Chevy header can be used, the Chevy flanges can be removed and Cad flanges can be made up quite easily. The primary tubes may need a bit of tweaking to line up with the ports with this method. Remember that the front and rear drive exhaust manifolds are different for the driver side. This may help in routing the exhaust if it is a tight fit on that side. | ||
| − | The Cad engines do not fit easily in | + | The Cad engines do not fit easily in some GM chassis. Never fit the engine in without putting the exhaust manifold on first. Better yet, use a custom set of block hugger headers, as Cad parts are usually insanely expensive (but worth it in this case). |
===Intake manifold=== | ===Intake manifold=== | ||
| − | Stock carbureted intake manifolds can benefit from a 1 inch spacer under the carburetor, adding around 15 hp. Because of the bathtub-type steel intake gasket, plate stock and exhaust tubing can be fabricated into a tunnel ram style dual carb manifold. You can build one of these to use a pair of Quadrajets from 4.1L Buick | + | Stock carbureted intake manifolds can benefit from a 1 inch spacer under the carburetor, adding around 15 hp. Because of the bathtub-type steel intake gasket, plate stock and exhaust tubing can be fabricated into a tunnel ram style dual carb manifold. You can build one of these to use a pair of Quadrajets from 4.1L Buick V6 or 4.3L Chevy V6 engines, as two of these with straight linkage could feed the big motor quite well. The bathtub gasket can be reused by using a bit of Permatex to seal the block and head surfaces by encircling the ports to prevent an internal vacuum leak on both sides of the gasket. |
===EFI=== | ===EFI=== | ||
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