429 to 500 engine swap???

    Heres the deal I have a 67 cadillac deville the car is a full custom show car, except the engine the engine thats in the car is a 429,this engine is original I can feel its getting weak!! What I have is 2 cadillac eldorados a 72 and a 75 each one of them are 500ci... Is there alot fab that needs to take place to make a 500 fit in this car if so what is it and also I will have one of these motors rebuilt there both in the same shape...What year is the better year for the 500s 72 or 75??????


                                    Thanks Jesse Osborne



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im just curious how much miles to the gallon those 500's get ...

On the big 75 or 76 you will get somewhere between 12 and 16 depending how you drive her, that's from memory from many years ago.
 
I don't know if there was a better year for the 500, as I remember one was just like the other from year to year, not 100% on that, but I would use the best of the 2, not sure about the mods, slowroll or one of the other guys may know.

    Heres the deal I have a 67 cadillac deville the car is a full custom show car, except the engine the engine thats in the car is a 429,this engine is original I can feel its getting weak!! What I have is 2 cadillac eldorados a 72 and a 75 each one of them are 500ci... Is there alot fab that needs to take place to make a 500 fit in this car if so what is it and also I will have one of these motors rebuilt there both in the same shape...What year is the better year for the 500s 72 or 75??????


                                   Thanks Jesse Osborne



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500 should be a relatively easy swap, your will need to change oil pan and oil pump pick up, transfer exhaust manifolds, and accessory brackets. There are several sites specializing in Cadillac 472/500 engines. Engines pretty much equal 1975 will have HEI.