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Building a more Powerful 429 Cadillac Motor

Discussion in 'The Hokey Ass Message Board' started by 64deville, Jul 8, 2006.

  1. 64deville
    Joined: Jun 25, 2005
    Posts: 147


    I've got a 429 from 66 Cadillac that I want to build for a project and have some questions. I've had other 429 Cad's but they were good enough that I really didn't want to rebuild them. This one burns oil like crazy and I'm going to tear it down. It was a common motor as it was used in pretty much every Cadillac from 64-67 but there doesn't seem to be much around for increasing power. It has potential as it was rated at 340 hp and I think a torque rating around 390 from the factory with around 10:1 compression. Having owned a few 429's that were factory stock and in better condition than this one I know they can be quite potent.

    Cant seem to locate any aftermarket cams, intakes, etc for this motor.

    Heres what I had in mind:

    Punching the block to .30 or .60 over, getting new pistons, rods etc.
    Moving to electronic ignition
    Custom cam
    Having the heads ported and polished

    Also heard of modifying a stock 429 intake to fit a larger Edlebrock carb but I've had pretty good luck with the Quadrajets in the past if they are properly tuned.

    Anyone else have any suggestions for this motor. Thanks in advance.
    Joined: Jun 3, 2005
    Posts: 8,220


    Regrinding a cam used to be somewhat common. I don't know much on the subject. Beyond that the head clean up and some custom built headers will wake it up. How potent do you want it? I'd shy away from real big valves and focus the head work on the pockets and get the exhaust matched up good. And hell yeah, a patient hot rodder can suck lots of power out of a Q jet. There's 2 "blank" chambers in the main carb body that can open to the main bowl and increase bowl volume (the Q jet's biggest flaw). Keep RPMs to 5000 or less and gear for torque then hang on. Dad and I stuffed many a Caddy into Ford pick ups back in the day. Had a stock 429Caddy in a 62 Ford SWB F100 unibody. I waxed a hopped up 72 Z28 with it in my senior year of HS. It had home built side pipes and a 4.10 gear. The guy was a bit pissed as I recall:D
  3. 64deville
    Joined: Jun 25, 2005
    Posts: 147


    I'm going to do something with the exhaust but I don't know about the headers. They will have to custom units and they will be a pretty tight fit against the frame and block. Planning to get dual Magnaflows (I think) and dump the pipes right behind the rear tires.

    Hadn't thought about the gearing. Definately more concerned about torque than overall horsepower as this motor will go into a big heavy Cadillac.
  4. 97
    Joined: May 18, 2005
    Posts: 1,904


    Courtney Hines, president of Cad Company, has "been there done that" . His 70 Coupe de Ville does 10s.....regular as clockwork. If he can't help , you can't be helped.

    Cad Company
    8333 Jefferson NE
    Albuquerque, NM 87113
    Tel: (505) 823-9340
    FAX: (505) 797-0627

    Online Catalog


  5. Toystoretom
    Joined: Feb 25, 2006
    Posts: 112


    I have a 66 Sedan DeVille Hardtop with the 429. I replaced the AFB with an Edlebrock 750 and made an adaptor plate from a generic carb adaptor/spacer, and used a chrome Edlebrock air cleaner. The AFB ran OK but it sucked gas like a pig. After I installed the new carb I picked up about 2 mpg IN TOWN and more than that on the highway. It also runs much better, this added several horsepower down low... I can shred the tires at will. I did have to buy the jet kit and rejet the carb... it was too lean at first. Very easy to tune an Edlebrock. I agonized over the 750 cfm being too big for a stock 429, and now that I have it on there I have come to the conclusion you could easily go 850, especially if you ran some sort of custom exhaust. My exhaust is stock, but I am planning to have some custom duals made up. Other than that my 429 is stock, about 77,000 miles and it runs really good.

    I am still fighting the driveshaft morons... this week I am going to order a used driveshaft and swap them out to kill my vibes...

    Oh... and just to let you know... I have found very little in the way of speed equipment for this. There is an intake but it runs dual quads (can you say 3 miles to the gallon) and it has no provision for the AC compressor. It would be OK in a street rod, but in a Caddy... I don't know.... I'm sure you can get a Pertronix... I'm using the stock points and so good so far. There is a lot more stuff for the later 472/500 Cads..

    Hey... you don't have the driveshaft out of that 66 do you?? PM me if you do...
  6. Those 429's will lay a black stripe off the RR tire of a '64 SDV 4D that will be there a year later.

    Trust me, I know.

    Might make more power w/ headers, duals, and cam...

    samurai mike likes this.
  7. oldcarfart
    Joined: Apr 12, 2005
    Posts: 1,437


    BTDT, just get a 472/500 & TH400 and do a swap, 429's are a money pit.

  8. 64deville
    Joined: Jun 25, 2005
    Posts: 147


    Dont have an extra drive shaft but mine vibrates like mad too.

    I'm kind of coming to realize that working with 429's aint cheap but I like to keep em original. Thought about the 472 swap but havn't looked into too much yet.

    A dual quad setup would be cool but expensive. I have AC but it don't care if it works or not, I've got these plates of glass on the side of the car called windows that I usually roll down. Its a summer car anyway.:)

    Its been puffing a lot of blue smoke lately so thats why I'm going to tear into it.
  9. FEDER
    Joined: Jan 5, 2003
    Posts: 1,269


    I got a 67 - 429 in My Merc. I looked for aftermarket parts and all I found was pertronix ignition and carbs that also are universal.
    Mine was a fresh rebuild and has more than enough power. With 279 - 8" single legger rear and the drive line dooin a drumroll on the floor for the first 100 feet it went 15.08 at 97 mph in the qtr. I still have points and the carter carb. Nice thing it gets 14 MPG on the highway. It does need a new dizzy and carb and Im sure it will run MUCH better.Delta could regrind Your cam and then You will need longer pushrods. I dont think Ide bother the stock cam works fine. You might just ring and bearing it,throw in a timing chain. Then do the valves with a little bowl work and a good 3 angle grind. I think You would be happy. Here a pic of a tri power set up I made for the 429. I used old Ford 406 carbs and linkage. Havnt put it on yet it hits the firewall in the Merc. DAM!!!! One of these days we will put it on. FEDER

    Attached Files:

    chriseakin likes this.
  10. Sanderson makes several headers that will fit the 429 engine. Just ordered a pair for mine. I'm going to go through the motor. I'm still looking for a cam, so I'll give you a heads up when I find a good one.
  11. The 429 was a common motor and I'll bet if you contact any of the older cam grinders, isky, or Erson come to mind you will find that they will grind you a cam from one of their older profiles. they don't throw that stuff away.

    Head work is always a good idea. even a pocket port job will clean one up and help a ton.

    I personally prefer the old AFB to the Edelbrock counter part but that is probably just a personal preference. A bigger carb is not always your best choice when building power it depends on what the rest of the motor has had done to it. I have seen 2x4 intakes for those around, they are pretty scarce but they have been made in the past and sometimes a 2x4 is a good choice, again depending on what else has been done.

    A good balancing and making sure that your main saddles are in align helps a bunch too. That is something that you don't have to source specialty parts for.

    zero decking and adjusting your quench to a comfortable .040 is always helpful, one is that it helps you keep things square and two it helps with pre detonation to keep your quench tight. .040 works for me others will have a different idea of course. I happened onto the number by accident and experimentation and it wasn't until this century that I found out that there is scientific basis for my findings. :eek: :oops:

    On a side note unless I am shooting for a specific cubic inch number boring is dependent on tolerances. IE I never bore more then is required to clean it up and make it right. I have found that if an engine will clean up at .030 there is no reason to go to .040.

    I have no doubt missed something here but that'll get the juices flowing.
  12. dan c
    Joined: Jan 30, 2012
    Posts: 2,214

    dan c

    i checked speedway--they list pistons, bearings, trans adapters, "mag-look" distributors, valve covers. that's about it from them.
  13. wsdad
    Joined: Dec 31, 2005
    Posts: 1,258


    Thanks for digging up this thread. It has answered a couple of questions I had.
  14. Me too, thanks for digging this up. I have a 67 Sedan DeVille with the 429 and this helped. Everyone says they can roast the tires at will...hmmm, I must be missing something as I can't for some reason...
  15. The Hyena
    Joined: Nov 29, 2004
    Posts: 141

    The Hyena

    Can i bump old of a thread to the top to ask a question ? I bought Sanderson headers for my 429 (66 Cadillac) and does anyone have a beat on a new alternator bracket ? or how to make one ?
  16. BJR
    Joined: Mar 11, 2005
    Posts: 6,984


    Why waste money on a 429 build when a 472 makes 375 HP and close to 500 ft lbs of torque bone stock. The 500 makes even more.
  17. Beanscoot
    Joined: May 14, 2008
    Posts: 2,042


    If memory serves, the 429 makes 340 HP and 480 ft lbs of torque, so not too shabby.
    My first car was a 1964 Caddy, as a result of overhauling its engine I assumed that fully machined combustion chambers were the norm, along with undercut exhaust valves.
    It turns out that most engines don't have quality features like this, excepting the early Hemis with their excellent machine work.

    My 429 had about 130,000 miles on it and was a fierce oil burner so I installed new rings. The compression and power were still great, but the oil burning was so bad that it would foul the spark plugs regularly.
    The con rod bearings were still good so I reused them.
    Since I didn't know better and had little money, I reused the steel shim head and intake manifold gaskets, which surprisingly (now that I know better) worked.

    The passage around the head bolt hole on each side that provides oil to the valve train was pretty well plugged up with the weird fine clay like deposits peculiar to the early engines. This caused severe wear on some of the exhaust valve tips, although I think only one didn't clean up with a valve grind.

    In those pre-internet days I also picked up a NOS 3x2 intake manifold with carbs cheap, discovered it only fit the earlier engines, and sold it cheap. Too bad I didn't hang on to it.
    The Hyena likes this.
  18. Beanscoot
    Joined: May 14, 2008
    Posts: 2,042


    I wrote my last post poorly, I should have said that the engine was a fierce oil burner before re-ringing it.
    After installing new rings, there was no more oil burning.

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