A Very Big Surprise: 1981 Porsche 911SC Sleeper

This 1981 Porsche 911SC is a really nice looking car that holds a bit of a secret. You look at the overall condition of the car and can’t help but think that it is owned by a person who truly loves their Porsche. If you really like this particular 911SC, then you can add it to your collection for what seems like a very reasonable $27,500, but even then the price is negotiable. The car is located in Newport Beach, California, and is listed for sale here at Hemmings.

There’s no doubt that the panels and paint on the Porsche look really nice. The wheels and tires are new, with 7″ wheels on the front, and 8″ wheels on the back. These are stock Porsche wheels, and the owner says that these are the largest wheels that fit the Porsche properly. Overall then, the external presentation is really impressive.

The interior of the Porsche presents as well, if not better than the outside of the car. The car has recently undergone a re-trim, and it is virtually flawless. There is an aftermarket stereo fitted to the car, but this is something that I don’t really have any issues with, as the work has been completed to a high standard.

Now we are starting to get into an area where this Porsche is more than slightly different and definitely interesting. You may find it strange that the owner has included photos of the back seat full of vintage leather luggage, and on the face of it, you’d be right. However, that luggage is a permanent fixture in the car, and it hides this Porsche’s party piece.

That luggage is actually a custom-made engine cover, and the Porsche’s original engine and transmission have made way for a 500ci Cadillac V8 and TurboHydramatic 425 automatic transmission. The owner says that the actual fitment of the engine and transmission took a bit of engineering, but not as much as you might think. The Cadillac package utilizes a single front and dual rear mounts, and the original Porsche mounts have been modified to suit. The engine itself isn’t standard, by any means. It has been bored, decked, fully balanced, fitted with forged pistons and conrods, and Bulldog aluminum heads. This produced a rather healthy 537hp on the dyno. The transmission has been fitted with a Trans-Go Shift Kit, which allows the torque converter to switch between low stall and high stall, as required. The engine is also fitted with a ceramic-coated exhaust, and a custom cooling system. The only real downside to all of this is the fact that the car can’t be fitted with a heater, so this is a car that is really designed for warmer climates. Speaking of climate: Even in the warm California weather, the owner has had no issues with keeping the engine cool.

So, there it is. A Porsche 911SC with a true sting in its tail. You might think that performing a modification project like this would result in a car that would be pretty ordinary to drive. If you did, then you’d be wrong. The seller states that the car rides well and sits nicely. This car may not appeal to everyone, but at $27,5000, it represents a lot of car and a lot of engineering for your dollar. I think that the owner sums it up best when he says, “When you pull that luggage off and your onlookers see those “Porsche 8.2 Litre” valve covers you’ll grin with delight at their complete bewilderment.”


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  1. canadainmarkseh Member

    Holy crap what a beast and well executed too. I do however think that this might be a little to much engine for this car. The power to weight ratio has to be rediculous and I’ll bet this thing is scary fast. I think even a 350cid would have been more than enough. Interesting find though.

    Like 12
  2. Rick

    Yes on the execution and no on the choice. That just made a butt heavy car even more so. I wouldn’t want to take a corner at any speed with this thing.

    Like 11
    • Cadmanls Member

      Rick it’s no longer a rear engine car, motors been moved, mid engine car now and am sure balance is better than original car.

      Like 7
  3. Cadmanls Member

    Have to wonder how much leg room is left? Has to be a real hoot to drive. Looks like a very nice build and worth every penny, Caddie motors are not cheap to assemble and dyno numbers look very nice.

    Like 8
  4. stillrunners stillrunners Member

    Wow….thought only Corvairs got that upgrade….maybe the owner got spanked a time or two ?

    Like 4
  5. Rock On

    With all of the exposure this car has received on the internet I’m surprised that it is still for sale.

    Like 5
  6. MikeG

    Sure you can have a heater, a couple of heater hoses off of the block and run them up to the heater core. Shouldn’t be that hard.

    Like 6
    • PVDave

      Ummm, Hello?

      ’81 911s were air-cooled, so no heater core present. (Now, you may have been going for ironic. If so, it was a swing and a miss…).

      Like 3
      • Andre

        This ’81 911 isn’t.. You can even see the water pump front and center in the pictures…

        Like 4
      • Derek

        …also, if you’ve managed to fit a V8 and its associated drive gubbins backwards into a 911 , then a couple of hoses and a heater core and controls shouldn’t be /too/ hard…

        Like 3
    • Todd Fitch Staff

      Nice one, Adam! I have to agree it’s funny the builder thought, essentially, Cad 500 in a 911 = “Not as much (engineering) as you might think,” but re-fitting or fabricating heat exchangers or adding a $35 heater core = just too mind-bending. lol http://forums.pelicanparts.com/porsche-911-technical-forum/524591-how-does-heating-system-work-74-89-a.html

      Like 2
  7. Steve R

    An aluminum LS engine would be a better choice. From the ad, it appears the swap was done around 2002 while Cadillac engines were the flavor of the month. This was also before most people realized how good the LS engines are.

    Steve R

    Like 4
  8. Rock On

    Sure the LS engine is the logical choice, but spanking someone with a Cadillac engine is so much more satisfying.

    Like 15
  9. UK Paul

    I was loving this car till the engine bit. Then I thought about it a while and maybe.
    I am divided I think.

    Like 3
  10. Andrew

    I am glad I used one of my “not yet determined” allowable views on this. I dig it.

    Like 4
  11. wuzjeepnowsaab

    OMG I love this! What a well thought out and brilliantly executed mod. The stance is perfect…way more perfect than I would have thought with that big heavy sledgehammer sitting over the back wheels.

    8.2 liters of torque slamming hp…It’s only a 302ci engine bigger than stock lol

    Like 2

    I’m the first guy to scream “restomod!”…for most cars on this site.
    To that end…I’m all for ripping this V-8 mod out…and going EV with it.

  13. moosie Craig M Bryda

    1. Sit down
    2. Hold on, Buckle up
    3. Shut up
    4. Clean up after yourself

    Like 5
  14. Michael Brooks

    Thanks for the nice writeup on my car Adam! It’s always amuzing hope many opinions are given. All hot rods are the vision of the creator and everyone would do it differntly. We all stop when we’re satisfied and our vision is complete. I saw this done in Peterson’s Engine Swapping No. 2 in 1974 and always wanted to build one myself. I offer it for sale not for the $$$ but to find someone who “gets it”. It’s fun to correspond with those intersted. A couple of comments…it’s not to much power and mellow to drive, I’m 6′-3″ and have plenty of legroom, it’s not loud inside. LS engine would be nice….but it wouldn’t be nearly as fun and you need to mate it to the mid engine drive system. Michael

    Like 2
    • wuzjeepnowsaab

      Hi Michael, what did you do to keep the back end from sagging? There must be some rear suspension upgrades to handle the weight of the big block, no? I love the build…must really scorch the tires

  15. Michael Brooks

    Just installed bigger diameter torsion bars. It was a long time ago but somehow 31mm comes to mind. Not possible to scorch the tires! With weight slightly forward of the rear wheels those tires stick! The front tends to lift. But because it is an automatic transmission you need to hold it in 1st and get to about 20 mph before opening the throttle wide. That’s when the engine shows its power. What the car truly needs is fuel injection. Because the cam has quite a bit of overlap I have issues with low/variable vacuum at idle….drive the carb nuts. Merry Christmas, Michael

  16. Del

    Porsche guys be laughing their asses off.

    Rightly so. Joke Car

    Like 1
  17. michael h streuly

    Very nice.

  18. Bobinott

    I just hope that luggage is Kevlar-lined! Back in the 1970s I used to race a car that had the engine located beside the driver. At my now wiser age, I reflect on how close I was to “death by shrapnel”. Nonetheless, this Porsche is really nicely executed. If you don’t get it, don’t buy it. Too bad Cadillac didn’t have a manual trans-axle….

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