Engine upgrade or swap

1979 CADILLAC DEVILLE
70,000 MILES • 5.7L • V8 • 2WD • AUTOMATIC
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BALOO MCFLY
  • MEMBER
  • 1 POST
Looking to get more power out of my car listed above trying to figure out are there any double hump heads that are compatible with the 425 or should I just swap for a 500 or 472 if possible?
Apr 20, 2022 at 11:43 PM
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STEVE W.
  • ✓Experienced Mechanic
  • 15,320 POSTS
Pretty much all of those are high torque low HP engines built to move land barges. None of them have real potential for HP without a good amount of work. With a good cam, intake, headers and some good tuning on a Holley the best I've heard on the 500 was around 400hp. Spend a lot more and you can get more HP but by then you have replaced pretty much everything but the block.
If you want to dig a bit try:
https://cadillacspeedshop.com/
Most of the parts work on all of the big Cad engines 368, 425, 472, 500 but none of them live long past about 4,500-5,000 RPMs without adding big money.
Apr 21, 2022 at 12:36 AM
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