Cadillac Hot Rod Page

The Cadillac Hot Rod Page

My car is a dark metalic blue 1979 Cadillac Sedan DeVille, it has over 119,000 miles on it now, I have put only 8,000 on it since I got it. It got about 17 MPG on the highway, and 11 MPG in the city, with the stock 425. I know it is no hot rod car, but it has a lot of potential for many reasons. First of all it has a large reliable 425 cu. in. (7.0 liter) Big-Block to work from, which is interchangeable with the 368,472,500 Cadillac engines! Second it is backed by a rugged TH-400 3-speed transmission, along with the famous GM 10-bolt rear that was used on millions of other cars! Another reason it has such good hot rod potential is because it is a Cadillac! How many fast powerful Cadillacs do you see out there? There are thousand of Cadillacs out there that look just like mine, but they won't be half as powerful after I get done with mine! I plan on installing performance parts, but make the Ol' Cad a big Hot Rod Sleeper looking car.

My dad purchased the car for me in March of 1997 from a couple in Horseheads, NY for $800. This isn't the cheapest you can get one of these 70's or even 80's Cadillacs, but it is in great shape and is a steal at $800, and it is a cheap start for a hot rod sleeper! I am the third owner, and I found out the first owner lived in PA, and traded in her 76' Sedan DeVille with only 23,000 miles on it for my new 79' Sedan DeVille. The body is in great shape, the paint is a little weathered, but the chassis and engine/tranny run beautifully. The car needed minor work to get it ready for inspection, like fixing the front passenger side body filler, which lost a bolt, and rubbed against the tire. After I fixed up everything that was needed for inspection, I had the car registered in August 97'. The interior of the car is also in great shape, it has white leather seats, light blue carpet, and an AM/FM 8-track player that still worked! I installed a new power antennae, which I got at Radio Shack for $30. The only thing wrong with the interior was the headliner, which was missing. I purchased a new one for about $120.

The first major move towards hot rodding my Cadillac was a tune-up. I started by changing the spark plug wires (which I believe were the originals), distributer cap and rotor, and I installed 8 new AC Delco Rapidfire spark plugs. After the tune up I installed a Accel High Energy HEI coil. After driving it around with just these Hi-Po improvements I decided to rebuild a Q-jet I got from the local junk yard, Pick-a-Part, for $17. It needed a new float $6, a rebuild kit $11, and new front and rear vacuum breaks $40. I planned on rebuilding the carb with performance in mind, so a complete cleaning and inspection was needed, along with the rebuild. I also decided to improve airflow by grinding down all the casting marks in the primary and secondary bores. After I installed my new rebuilt Q-jet, I was amazed at the performance increase! This was primarily due to the fact that the secondaries on the original carb did not open all the way, and I also think the airflow improvements I made also helped. I knew I had more power by how much easier it was for the torque monster to spin the rear wheels.

I was planning on installing Hooker Headers #2455 $166, which are for the big-block chevy, and I purchased a header flange kit from Cadillac Motorsports Development for $70. This allows the BB Chevy headers to bolt to the Cadillac 425/472/500 engine heads. I could not get these to fit the tight engine bay of the 79, so I am looking into installing Sanden block hugger headers. I also plan to install a 72 GPH Carter Electric fuel pump $45, to feed the hungry 472, with a canister type fuel filter, I am also using a fuel pump block-off plate, which I also purchased from CMD for $20. This is all going to get fuel from a 16 gallon fuel cell mounted in the trunk. For the TH-400 tranny I installed a shift improver kit $25, and a chrome fluid pan with a drain plug. I was seriously considering nitrous oxide on the 425 for an extra 150 hp, and then I would get lots of power easily right?, WRONG!!! Through my research I found out the the 425 uses a lighter therefore weaker crankshaft than the 472,500, I have heard many horror stories of people snapping the crank on their 425 by racing it or adding nitrous. I quickly decided that my only option was to install the 1972 472 that I was considering earlier, and then possibly add massive doses of nitrous because this engines crank can handle it!!!! So, I went to Pick-A-Part ( My home away from home!) on the hottest day of April, and pulled a 472 myself. The donor car is a 1972 Cadillac Fleetwood Brougham, a very large Luxo-barge! The 472 had only 98,066 miles on it and it was in there because the car frame had rusted out. The engine was $50 plus some torching and impact wrenching that was needed to get the motor mounts and exhaust off, which added to the price along with a core charge. The total price came to $166. I got the engine home and on the stand and began to take apart the oil leaking grease ball. I was amazed at how clean the inside of the engine was, there was almost no wear in the cylinders, almost no carbon deposits on the heads or pistons! My plans are to inspect the engine futher, check tolerances, hone out the cylinders and install new oil pump, water pump, and timing chain set, bearings, piston rings and top it off with a good gasket set. I will then add a new coat of Cadillac light blue paint to make it look like the less powerful 425, to maintain the sleeper look on the inside of the car. Then with the headers, dual exhaust system, Edelbrock performer intake manifold, Holley 780 carb, Competition cam and other modifications like milling down the heads to raise the compression, I estimate the new total power of this Luxo-barge to be close to 430 Horsepower!

1979 Cadillac Sedan DeVille specs:

Base Price  $11,493 (1979)-All prices are 1979
Options on my car.
Leather Seats            $350
Dual Power seats         $402
Cycle contolled wipers    $38
Tilt, Telescoping Wheel  $130
Power Door Locks         $121
Lighted Vanity Mirror     $50
AM/FM 8-Track            $195
Padded Vinyl Roof        $225
Chrome Molding            $90
Accent Stripes            $56
Carpeted Floor Mats       $36
Wire Wheel Covers        $292
Door Edge Gaurds          $13
Twilight Sentinal         $56
   (Headlights can come on automatically at night and stay on for a
                        adjustable time after the car is turned off.)
Opera Lamps               $66
Total Price W/Options  $13,603
Motorhead specs:
Engine 425 (7.0 Liters) OHV V-8
  Bore & Stroke 4.082x4.06 in.  
  Compression: 8.2:1
  Horsepower: 180 HP @ 4,000 RPM
  Torque: 320 LBS-FT @ 2,000 RPM
Transmission:  Three Speed Turbo Hydramatic (TH-400)
          (1st. 2.48:1, 2nd 1.48:1, 3rd 1.00:1)
Wheelbase 121.5 in.
Length    221.5 in.
Height     55.3 in.
Weight    4,212 lbs.
Production Total 93,211 (Sedan DeVilles-1979)
  1972 CADILLAC 472 SPECS. (7.7 Liter)
Bore & Stroke:  4.3 x 4.06
Compression ratio:  8.5:1
Horsepower: 220 @ 4400 RPM 
Torque:  360 lbs.-ft. @ 2200 RPM
Carb: Rochester Q-Jet 750 CFM
This engine is from a car that weighed almost 700 lbs. more than my 79'.
           It should make the 79' a bit more peppy!
The Modified 472 will have the following:
   
   Holley 4160 780 CFM carb
   Edelbrock Performer intake manifold
   Competition Cam
   Reworked HEI ignition system
   Ported Heads
   Compression at 9:1
   Dual Exhaust and someday headers
   425 Pulleys and accesories- Alternator, Water Pump, A/C Compressor
For those who are interested in Hot Rodding their Cadillac, I purchased, 
or I am planning on purchasing most of my power products from Jeg's, Summit, 
and Cadillac Motorsports Development and Maximum Torque Specialties.  If you 
have any questions about this page or, want to talk about Cadillac's, 
or Hot Rodding your Cad, you can e-mail me through the link below.  
MTS sells a great engine tech guide for the big block Cadillacs that is
 around $10, and is full of great info!
        Cadillac Performance parts suppliers Phone #'s
  Maximum Torque Specialties (MTS): 414-740-1118
  Cadillac Motorsports Development (CMD):  941-648-5114  Catalog $4
      a.k.a. Cad Company  
==========================================================================================
                CADILLAC BIG BLOCK INFO:                                                     
  The Cadillac Big Block engines were made during the following years.
  Engine size (cu in)  Liters    Cylinder head size (cc's)                               
Years                                                                                
  1968-1974     472     7.7             76cc                                              
  1970-1976     500     8.2             76cc (1970-1972) 120cc (1972-1976)                
  1977-1979     425     7.0             96cc   Smaller ports than 472 or 500              
  1980-1984     368     6.0             Cylinder heads do not interchange with 472 or 500.
   The early 76cc head must never be added to a later 120cc engine without changing the connecting rods and pistons.
This could result in around 13:1 compression and some broken
valves.  120cc heads on a 76cc engine will produce around 7:1 compression.  
The 425's  96cc heads can be made to fit a earlier engine, but the ports must be machined to match the intake manifold ports.
  The Cadillac big block engine weighs around 595 lbs complete, and with an aluminum  intake manifold, 22 lbs. is saved. 
This makes the Cadillac big block lighter than a big block chevy,
with more cubic inches, and only 75 lbs. more weight than a small block.  The Cadillac big block is so light, yet reliable and strong because of the high nickel alloy in the block.  
This is more expensive to produce, but allows for less cylinder wear.  One of these engines with 100k miles on it is hardly worn, as with my 98k mile 472 that showed almost no cylinder wear.
  The big block Cadillac was not performance oriented coming from the factory.  The intake and exhaust manifolds are the most restrictive ever made!  The intake manifold weighs a ton, and is
actually a low riser, the air/fuel mixture must travel UP to get to the cylinders!  This works, but is far from performance. 
The 472,500 intake manifolds are dual plane and the 425 manifold is
a single plane, therefore not as much of a performer.  The Edelbrock Performer aluminum intake manifold that I plan to install on my 472 rasies the carb 3 inches, weighs 22 lbs. less and can 
add 20 hp!  The Edelbrock manifold will not allow the use of the stock air conditioning compressor, 
but Sanderson or Vintage Air make compressors that fit these engines.  I have read that the stock 
Q-jet is a great carb, along with Holley 850's or an Edelbrock.
  The exhaust manifolds, like on most cars, are not very efficient.  The 472 and 500 manifolds flow better than the 368 or 425 manifolds, but are still terrible. 
A set of even poorly made headers with single exhaust is a great performance upgrade.  These manifolds can be made by cutting
off the flanges from a BB chevy and welding on Cadillac flanges, or buying the already made block hugger headers from Sanden (~$250).
  The stock camshaft is made with built in retard, and is also not a performer.  CMD and MTS make cam kits that go from mild to wild. 
The stock valve springs can't be used on some of their hotter 
cams, but they sell spring kits that allow the use of their cams below 5,000 rpm's.  Above 5,000 rpm's the stock rocker arm retainer clips can break off causing the cylinder to go dead.  Several
companies make roller rocker arms that are expensive, but add a few hp from less friction, and allow for higher revving and larger cams.

My modifications:

I changed the rear plastic body fillers which were cracked and broken. I purchased two used ones from Pick-a-Part for $5, I painted them the original color and installed them. First I took off the massive chrome bumper, which was about six or seven feet long, and weighed a lot, I noticed it had several steel spacer plates used for alignment. I removed the plates and noticed that a few of them were rusted badly. There were a total of seven of them 4 on the drivers side, and 3 on the passengers side. I weighed one and it weighed 10.3 oz. With seven of them hanging in the rear it adds up to several pounds. I decided to make new spacer plates out of aluminum. I used the old steel plate as a guide, and drilled pilot holes on one side in two places. I then used a band saw to make the slots to slide the spacer plate onto the mounting bolts. In case you were wondering, the spacer plate looks like a long E. These new spacer plates weighed an average of 3.3 oz., down from 10.3. This reduced the weight by two-thirds, which is good for performance! I hope to some day replace the spacer plates on the front bumper also, and try to find other ways of reducing weight. I have seen other Cads with custom made aluminum bumpers, so I'll have to look into that! I have a 1978 FB that will be my donor car for and aluminum hood, and I am also using a aluminum radiator and possibly some electric fans to save weight and add power.

I also installed the B&M shift improver kit in the trans., which claims to improve the shift for a firm feel, and increased transmission life. I used the set-up for heavy duty and towing along with a racing filter for the TH-400 and a chrome pan with a drain plug. I also installed dual high flow catalytic converters I bought from Summit Racing $85. It is alot smaller and lighter than the original one and claims it flows 26% more

I installed a new JVC 35wX4 CD player and it sounds awesome! I had previously installed dual Pioneer 80 watt 6x9's in the rear and dual Pioneer 60 watt's in the front. I did not install the covers that came over the stock rear speakers, so this helps the bass amplify in the cavernous trunk. The car literally shakes from the bass and the sound is much clearer and better sounding, but you can't see out the rear view mirror because of the bass!

Here is what my car looks like all polished up!

Here is my Cad with the new engine (broken in of course!) doing a good ole smokey burnout! I just love to smoke cheap retreaded snow tires! Notice the gray aluminum hood that weighs a ton less than the stock heavy steel hood! Hopefully after I get the engine all tuned and running good I can get some paint on this beast so it doesn't look as much like a beater! It's the fastest ugliest car around now though!

My Cadillac Page Links!

The 484 engine project page: Part two of my Cadillac hot rod project, it is a must see page!
The 1976 Cadillac Fleetwood Brougham Page: My 1976 Fleetwood Brougham, the pride of my fleet!

Sean Janne

caddydaddy472@yahoo.com

Here is a tribute to my past Cadillac's:

My 1976 CDV (Brown) and My 1975 SDV (Blue), both which have gone to the junkyard in the sky! R.I.P.

Deceased is my 78' Fleetwood Brougham with the 76' 500. After about three weeks of awesome fun with the 500 powered Fleetwood, the 226k mile engine developed deadly main bearing knock, and has also gone to the great junkyard in the sky as of Sep 6th, 2001. The aluminum hood has gone onto my '79, so the Fleetwoods legacy still lives!