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I am new to this so please bear with me. I have a 1996 Eldorado with just over 100,000 miles. I am told the head gaskets are blown and the est. is $4,500 to fix it. I have a friend at the local Chevy dealer who will sell me a new motor for $4,600 so there is a no brainer there! I have looked on Ebay for a used motor and have been told that any 4.6 Northstar motor is the same it's just the difference in the coil packs and computer that make the engine what it is. I know there were two versions of the Northstar a 275 HP and a 300 HP version. Mine is the 275 HP version. I love the car and am not too worried about the cost to fix it but I would like to know if i could upgrade to a newer version or am I just going to have to use a 275 HP motor that is coded for my car. I have located a motor from a 2002 ETC which comes with the coil packs and computer. Could I use this motor? I would request some help because when I asked the local Cadillac dealer repair manager he told me to buy the motor from Cadillac and have them install it total cost $9,500. Thanks and have a nice day!

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I am new to this so please bear with me. I have a 1996 Eldorado with just over 100,000 miles. I am told the head gaskets are blown and the est. is $4,500 to fix it. I have a friend at the local Chevy dealer who will sell me a new motor for $4,600 so there is a no brainer there! I have looked on Ebay for a used motor and have been told that any 4.6 Northstar motor is the same it's just the difference in the coil packs and computer that make the engine what it is. I know there were two versions of the Northstar a 275 HP and a 300 HP version. Mine is the 275 HP version. I love the car and am not too worried about the cost to fix it but I would like to know if i could upgrade to a newer version or am I just going to have to use a 275 HP motor that is coded for my car. I have located a motor from a 2002 ETC which comes with the coil packs and computer. Could I use this motor? I would request some help because when I asked the local Cadillac dealer repair manager he told me to buy the motor from Cadillac and have them install it total cost $9,500. Thanks and have a nice day!

You need to use the 275 HP version. The 300 HP engine will not perform properly in your car dur to the difference in final drive ratio. Also the camshafts are different between the 275 & 300 HP engines - I can't remember if it is the intake cams, exhaust cams or both...

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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All Northstar engines are NOT the same! While it is true that the basic engine looks similar year to year, there were many changes. The horsepower difference is of least concern, either rating will work OK.

There were many subtle changes from year to year. The 93-94 will interchange easily, one small change was the PCV valve changed location, that is an easy modification.

While some years will interchange, it is best to get the correct year and model, for your car.

95' and up I am not sure which years are able to interchange. Engine sensors changed location, and voltage required to make them work correctly changed, the PCM changed, etc. Later engines had different ignition sensors, and locations.

There was a list that showed which year Northstars interchanged, but I no longer have it.

Trying to get a Northstar to run in the wrong year combination, is a real headache at best and sometimes just not possible.

Get the replacement engine identification number (it will identify the year and power rating), and then ask the dealership if it will work in your car.

-George

Drive'em like you own 'em. - ....................04 DTS............................

DTS_Signature.jpg

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I would stick with a 1996-1999 engine, since the LD8's made between those years are pretty much the same. As far as using an L37 engine, with the tranny fomr an LD8...that's bad idea. Not only do you have less low end torque, but you have a taller final drive ratio. The exact opposite of what you want. The car would have much less pickup than it did, that why the L37 uses the 3.71:1 final drive ration, and the LD8 uses the 3.11:1. On the flip side, an LD8 engine, and a trans fomr an L37 car is a great match. That's what they used in the Bonneville GXP and are using in the Lucerne now I believe. Of course that would require a tranny swap, and PCM reflash so it would work with the different final drive ratio.

Almost forgot...L37 (300hp/295lb/ft-tq_3.71:1 Final Drive) LD8 (275hp/300lb/ft-tq_3.11"1 Final Drive).

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I am new to this so please bear with me. I have a 1996 Eldorado with just over 100,000 miles. I am told the head gaskets are blown and the est. is $4,500 to fix it. I have a friend at the local Chevy dealer who will sell me a new motor for $4,600 so there is a no brainer there! I have looked on Ebay for a used motor and have been told that any 4.6 Northstar motor is the same it's just the difference in the coil packs and computer that make the engine what it is. I know there were two versions of the Northstar a 275 HP and a 300 HP version. Mine is the 275 HP version. I love the car and am not too worried about the cost to fix it but I would like to know if i could upgrade to a newer version or am I just going to have to use a 275 HP motor that is coded for my car. I have located a motor from a 2002 ETC which comes with the coil packs and computer. Could I use this motor? I would request some help because when I asked the local Cadillac dealer repair manager he told me to buy the motor from Cadillac and have them install it total cost $9,500. Thanks and have a nice day!

You need to use the 275 HP version. The 300 HP engine will not perform properly in your car dur to the difference in final drive ratio. Also the camshafts are different between the 275 & 300 HP engines - I can't remember if it is the intake cams, exhaust cams or both...

I am new to this so please bear with me. I have a 1996 Eldorado with just over 100,000 miles. I am told the head gaskets are blown and the est. is $4,500 to fix it. I have a friend at the local Chevy dealer who will sell me a new motor for $4,600 so there is a no brainer there! I have looked on Ebay for a used motor and have been told that any 4.6 Northstar motor is the same it's just the difference in the coil packs and computer that make the engine what it is. I know there were two versions of the Northstar a 275 HP and a 300 HP version. Mine is the 275 HP version. I love the car and am not too worried about the cost to fix it but I would like to know if i could upgrade to a newer version or am I just going to have to use a 275 HP motor that is coded for my car. I have located a motor from a 2002 ETC which comes with the coil packs and computer. Could I use this motor? I would request some help because when I asked the local Cadillac dealer repair manager he told me to buy the motor from Cadillac and have them install it total cost $9,500. Thanks and have a nice day!

You need to use the 275 HP version. The 300 HP engine will not perform properly in your car dur to the difference in final drive ratio. Also the camshafts are different between the 275 & 300 HP engines - I can't remember if it is the intake cams, exhaust cams or both...

Hey thanks for the help...I am going to buy the new motor and have it installed. The car is too nice to have sitting in the garage!

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