DeRat! 1964 Big-Block/4-Speed Cadillac

GM, for years, had a very defined dichotomy. Chevrolet was the anchor brand, economically priced and powered by six-cylinder engines. Cadillac, at the other end of the spectrum, meant quiet refinement, luxury, and smooth, substantial V8 power. As the years went on, Chevy wanted part of that and went to great lengths with its raucous power line-up of small and big block V8s, engines that went way beyond the “smooth, substantial V8 power” provided by Caddy. Here’s a thought, what happens when you blend the two? You’re about to find out with this kit-bashed 1964 Cadillac Coupe DeVille. It’s located in Coral Springs, Florida and is available, here on craigslist for $27,000.

Back in the day, there was a famous drag racer named Bill “Grumpy” Jenkins, a Cornell University-trained engineer from Malvern, Pennsylvania. He was a real tinkerer and an early joiner/creator of NHRA’s Pro-Stock class (I actually saw him knock out Ronnie Sox’s Hemi powered ‘Cuda with a small block-equipped Vega at an NHRA night meet at Capitol Drag Raceway in ’72). Anyway, the Grump pioneered these tall box-like hood scoops that were known colloquially as a “Grump Lump” and darn if this Caddy isn’t wearing something very similar to one – the first indication that this isn’t a country club Coupe DeVille.

Beyond that, the mono-color, razor-sharp slab sides of this Standard of the World, give further indication that this coupe is something special. It’s a refrigerator-white finish, but it must be a mile deep. Slam it, give it Vogue steelies, and a south Florida heavy window tint, and voila! – this is a serious-looking cruiser.

Originally harboring a Cadillac 340 gross HP, 429 CI V8 engine, coupled to a Turbo-Hydramatic automatic transmission, this beautiful beast now possesses a Chevrolet architecture Merlin 454 CI V8 “rat” motor working via a four-speed manual transmission. Little is said about the powertrain swap though the engine is equipped with an aluminum intake manifold and a Holley carburetor, at the least. I’m certain there’s a lot more that can be listed but an inquiry will need to be made. Unfortunately, there’s no word as to how this transplant motivates but I imagine it’s very noteworthy!

The interior is rather unremarkable, it looks mostly Cadillac-like other than that very obvious, and lengthy, four-speed manual gear shifter. The seating upholstery, which is in fine shape, may or may not be original Cadillac fare, I couldn’t find a clear example of the standard ’64 material that was employed. The carpet is a bit worn, but it’s mostly covered by some rather groovy floor mats. One interesting observation is that the original, wide automatic transmission brake pedal is still in place, with what looks like a much smaller clutch pedal to the far left – I’d really like to know how all of that came about and is connected. Oh yeah, the A/C actually works!

Like it? You bet, how could I not? Whether you do or don’t, you have to appreciate the sense of imagination, and mechanical skills, that went into creating this one-of-a-kind Caddy, right?


  1. Nevadahalfrack Nevadahalfrack Member

    A good display of a mechanical paradigm in seeing something differently and creating it. The Merlin BBC is good for at least 575-600 HP IIRC, and with a 4spd it’d be a hoot. The “Grump lump” (haven’t heard that term in YEARS) is an “in your face” expression as is the slam and oversized rims. Not a fan of the slam and big rims but that’s the owners style and more power to him for showing what he can do. The clutch pedal is an interesting fabrication, and speaking of fabrication what’s with the extra knobs and fuse panel I wonder?
    However IMO what he really should do is a deep clean to the seats and carpet!!! The back seat is just ok but the drivers side from looks like the front door carpet in a low rent apartment (been there/done that); the drivers side carpet looks like someone spilled a cheese dip on it and did a really bad job of cleaning up afterwards..
    Interesting cruiser and probably would’ve been a big hit on Whittier Blvd. back in the day though a little rough around the edges-but it’s their expression of what’s cool from their viewpoint and how can you fault that?

    Like 12
  2. 19sixty5 Member

    Interesting… I’m not a fan of the monochromatic look, but this looks better than most. The hood scoop, well, if it actually needed a scoop would be one thing, but I could do without. It would be interesting to drive with that pedal arrangement, it has to be a hydraulic clutch setup. Again, “interesting” car. I have to confess I sort of like it, except for that hood scoop!

    Like 12
    • RexFox Member

      Having mostly owned trucks and small European cars, I’ve often thought it would be nice to have a big Caddy for road tripping, but I like to choose gears. Well, this is my chance to have both, but for some reason, I’m going to pass.

      Like 0
  3. 370zpp 370zpp Member

    “Grump Lump” looks more like “Casket Lump”.

    Like 8
  4. bobhess bobhess Member

    I may be off on this but this car doesn’t look like its been slammed. Don’t see where the lump was necessary but a good looking car any way. Not sure about the wheels fitting the car itself but to each his own. Should screw up someone’s mind at a stop light drag.

    Like 6
    • Jim ODonnell Staff

      Maybe “lowered” would be a better term. To my eyes, this Caddy looks as if it’s sitting noticeably lower to the ground than a stock edition.


      Like 9
      • Kevin

        72?, In irwinville,LA?
        The night Fat Rat Russell jumped?.

        Like 0
      • Jim ODonnell Staff

        Gambrills, Maryland


        Like 0
  5. angliagt angliagt

    I agree about the hood scoop.This would be a
    perfect “Sleeper” without it.
    My Dad had a ’64 Coupe de Ville.I love the style
    of these,but would have no desire to ever own one.
    These were great highway cruisers.

    Like 3
    • Ike Onick

      I may have asked this before and I’m not picking nits, but does anybody under 60 know what the term “sleeper” means? Just curious, that’s all. IIRC “sleeper” applied only to street drag racing back in the 1960’s. In particular, stop light drag races.

      Like 4
      • Nevadahalfrack Nevadahalfrack Member

        Well, that term in my Georgia family was originally used back in the day when one of the “neighbors” built a car to run ‘shine; we used it out here when we saw something that looked like mom & pops car but something else more potent was lurking underneath.
        Maybe I learned it wrong, but there’s our explanation for the usage of that expression.

        Like 10
  6. Dave

    It might be bagged. You’d have to get used to shifting up and down instead of fore and aft. Another reason to stay with an auto, besides the badly placed clutch pedal

    Like 2
  7. CCFisher

    Love the concept, not a fan of the execution. The grille bars are uneven, the box on the hood is pointless, and the color looks like clearcoat over gray primer.

    Drop the nose to give it a bit of a rake, ditch the monochrome look, paint it a metallic dark gray, reinstall the missing trim, reupholster the interior in red, and install a set of oversized American Racing Torq-thrust M wheels.

    Like 5
    • B302

      I do not want any vehicle in any silver or gray color at all. Most cars/trucks today are available with ten different shades of silver and gray, two or more in black (I never imagined that a vehicle would be available in two different blacks, but it is not uncommon today). Vehicles today are not offered in colors, only shades, or as a traveling buddy of mine commented, he saw more car colors on Red Square in Moscow and Tiananmen Square in Beijing.

      Like 4
      • Burt

        You want light black or dark black?

        Like 2
  8. Dave

    I like where this caddy is goin

    Like 1
    • Lahrs

      That clutch conversion takes some skill, but can be done. Love the original interior

      Like 2
      • Chuck Dickinson

        The interior is about as original as the exterior. Aftermarket cloth which is not even close to original, but the rest appears stock, including that hideous light gray/green color. I had a 64 convert, which, unfortunately, had that color inside. I vinyl-dyed it to a more pleasing green to match the paint color chosen (64 Eldorado Emerald Firemist).

        Like 0
  9. Kenneth Carney

    Lose the lump! I agree with CC Fisher
    on restoring the exterior to ’64 Cadillac specs. Right now, it’s too much in your face for me. After all, what we have here is a great basis for
    a gentleman’s hot rod. Hope the 4-
    speed is a rock crusher. Finally after
    all these years someone built a
    Cadillac with an attitude.

    Like 3
  10. ACZ

    The shifter and clutch pedal need to be redone. They look amateurish and unsafe. The hood has got to go! The rest seems pretty good.

    Like 0
  11. Robert Levins

    Basically it’s a really cool car with a lot of different possibilities. Everything I’ve read so far that folks have mentioned, really sounds like fairly easy fixes, or modifications if you will. (You’re not restoring it from the ground up). This also looks like a car that a “Large” person would drive/buy and would have no problem getting in or out. It’s a lot of everything. I do like it. I better, I’ve owned Cadillacs since high school. First one was a Cadillac Eldorado (1974) 500ci . Not new at the time, (7 yrs old in 1981) $1,600.00. Sunroof too. Any way, this Caddy probably has a starting price of about $18,000.0 the way it sits. But hey, it would make a great project. Good luck to all. Great article too.

    Like 2
  12. BA

    I have only one thing to say 1971 Corvette LS5 454 , 4 speed , Holley double pumper , A/C , The Rat that got away!

    Like 2
  13. pwtiger

    Yes, dump the lump. I’d like to see a pair of plush bucket seats and a console.

    Like 1
  14. Thomas L. Kaufman

    Looks like a poor man’s Pimpmobile. Just need a few accoutrements.

    Like 3
  15. Roger

    Is the blue accessory parting brake included in the price?

    Like 1
  16. Don Leblanc

    That “Lump” is so wrong, just kills the look of an otherwise nice condition Caddy.

    Like 0
  17. Sam

    I grew up in Pennsylvania. Watched Grumpy and Bruce go down the 1320 many of time. This looks nothing like a GRUMP LIMP. JMHO It looks like a casket lid. Now that would’ve looked good on the 1962 Hearse my buddy had in High School. He wrecked his 442 and got the caddy cheap, Auto Shop was the thing back then. Well the Caddy ended up with a 400 Olds and a 4 speed in it, But the pedals came out of the Olds. I like this but like everybody else, LOOSE THE LUMP. If your the one to buy it change what you want, Make it yours, Right now it belong to the seller and it looks like a few other nice rides sitting arounf so someone got something going good

    Like 0
  18. Big C

    I’d take this Caddy any day over the ’64 Eldo that just ran through Barrett Jackson. The one with the Tesla burn pit powering it.

    Like 1

    The Chrysler / Plymouth Factory bosses boycotted Pro Stock in 1972 because NHRA forced the HEMI cars to carry hundreds of pounds more weight so everybody else would have a chance at being competitive against a HEMI. Ronnie Sox was not there. The small block cars were allowed to run even lighter. Glidden went to a 351 Pinto and Grump fielded a small block Vega. It was a shame about Pro Stock. The other motors did not have a chance of competing with the output of the HEMI cars unless they weighed them down. Look it up in the 1972 NHRA rule book. I know because I was there…..Please don’t jump all over me. I did not do it. NHRA did it.

    Like 0
    • Jim ODonnell Staff

      I’m not about to jump all over you, but I assure you that I saw Grump VS. Sox at Capitol Raceway in Gambrills, MD somewhere between February and April of ’72. Grump took it with a 331 CI V8-powered Vega – Sox was there and I know, because I was there too.

      BTW, check out this article:

      About the 18th paragraph or so, in particular, which states, “Combined with the 331-a 327 bored .026-inch-and Borg-Warner T-10 (though he would rotate among a number of Muncies and a Nash five-speed during the season), Grumpy’s Toy IX debuted at the 1972 Winternationals, qualifying with a 9.90-second pass, but plowing through the field of Hemi-powered cars with passes in the low-9.6-second range to win the event. Unlike his previous Winternational win, this one heralded Jenkins’s first Pro Stock championship”.


      Like 0

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