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1968 Cadillac Deville
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6 Posts
Discussion Starter #1
Well after a few years of thinking about it I finally bit the bullet.

1968 Cadillac Deville Coupe...

I could use your help as to what to keep and what to upgrade. I have a pretty clear idea of the body, paint and interior. I know the 472 is a solid engine but could use some help upgrading.

  • Intake
  • Headers?
  • Carb?
  • Distributor
  • ECT...
Thanks and here are some pics...

00R0R_iAZIT541TRp_600x450.jpg 00909_4Ng27Pu8M45_600x450.jpg 00R0R_iAZIT541TRp_600x450.jpg
 

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1970 Eldorado, 1968 DeVille convertible
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68 Posts
Nice coupe, nice colour! I'm just in the proces of changing the timing set and converting to HEI on my '68 convertible. Check if there's slack in your timing set. These timing sets need to be replaced if you still have the stock sprockets/chain. I will post a thread about the HEI if i'm done with all the work, still waiting for al the parts to arrive ;-)
 

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Something German S550, 69 Eldorado, 68 Impala, If I tell you the rest, well
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529 Posts
Nice car. I like 68 with the stacked headlights one of my favorite years. First keep the carb is yours orig, or at least a qjet either way keep it is a really good carb. You can upgrade the dist to hei, I definetly would, but nothing wrong with points. No point in changing the intake, with a different don't think there would be hood clearance. Why headers? You can, the original manifold is pretty good. What's your plan for exhaust. I got straight pipe with glass packs.
 

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1970 Coupe De Ville//Cessna 172
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551 Posts
What is your reason for upgrading anything? I would suggest driving it for a while and see what it needs. She'll tell you what needs replacing right out of the gate. Then go from there.
I am a purist so I can't give an unbiased opinion. No need to change perfection!
Jeff
 

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1968 Cadillac Deville
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6 Posts
Discussion Starter #7
Thank you all.

I have no idea at this point what I am going to do with the engine.

Part of me wants to keep the orginal 472 and pump it up. Supercharge, Intake, FI, HEI, ect....

The other parts wants to do what I orginally planned which drop and LQ9 and change the bottom end of the car to a modern car.

I am weighing the options and want to hear from as many people as possible to assist in making the right choice.

Thanks...

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What is your reason for upgrading anything? I would suggest driving it for a while and see what it needs. She'll tell you what needs replacing right out of the gate. Then go from there.
I am a purist so I can't give an unbiased opinion. No need to change perfection!
Jeff
:) I understand but the part of me that needs to tweak my rides assures me that I am making the right choice.
 

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1968 Coupe DeVille
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24 Posts
Nice!! I've got a 68 CDV myself. Always good to see another 68!!
As far as upgrading, just know that at almost 5000 pounds with highway gears, it's never going to be fast short of a ton of work. But, you can help out the 472 with the regular upgrades like heads, cam, and intake. The Quadrajet is actually one of the better carbs you can put on these motors, and aftermarket carbs like Holley and Edelbrock are often mileage and power detriments on stock or mild engines. If you are considering or need to replace the carb, get yourself a good rebuilt q-jet. I got mine from a company called Autoline, and am pretty satisfied with it. First and foremost, it's got ethanol-safe rubber and plastics, so that makes it a worthwhile job just for that.
One of the best low-buck upgrades is replacing the intake manifold with an Edelbrock unit. You can see the relatively, flat, short runners on the factory intake. The Edelbrock unit lengthens these, and adds power where these tanks need it, down low. But you do have to make concessions for an air cleaner, and remove your A/C compressor. http://www.edelbrock.com/automotive/mc/manifolds/cadillac/performer.shtml
HEI upgrades are always a good idea, but unless you drive your car a lot, it may not be worth the upgrade alone. If you do other engine mods, definitely do it. If you stay mild, a good set of heavy duty points will do you just fine. I run Accel HD points in mine.
The TH400 trans in these cars is pretty stout, so if yours is in good working order, you can probably get away with a convertor and shift kit, if you really want to make the most out of any added power. You may need to get your trans built if you really go big with the power numbers. Anything over 550-600hp would be a safe bet.
Upgrading the rear gear is a definite if you want more than a cruiser. They came with a 2.94:1 gear ratio, which is really tall. Trouble is, there isn't much out there for the factory Caddy rear end, so a swap may be in your future should you get serious with the power.
For everything else engine related, check these guys out, and good luck with it!! http://www.cad500parts.com/
 

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Something German S550, 69 Eldorado, 68 Impala, If I tell you the rest, well
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529 Posts
Thank you all.

I have no idea at this point what I am going to do with the engine.

Part of me wants to keep the orginal 472 and pump it up. Supercharge, Intake, FI, HEI, ect....

The other parts wants to do what I orginally planned which drop and LQ9 and change the bottom end of the car to a modern car.

I am weighing the options and want to hear from as many people as possible to assist in making the right choice.

Thanks...

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Keeping it stock or modernizing it, either way you can't go wrong. I love both equally do what you want. Just to throw this out, I like ripping the guts out of an old car and making it new a little more.
 

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1970 Eldorado.
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4,023 Posts
If you are looking into getting a lot more power out of your Cadi you contact cad500parts.com. Lots of knowledge and parts there. I got my headers from there.
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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6,738 Posts
I assume you've inspected the brakes? or have service history on them. Not knowing where in the world you live I can't comment on rust. First thing I do with any older car is establish a baseline for safety. BRAKES, then cooling system then hoses. Then once its deemed safe do I think about mods. Reading what your plans are, it sounds like you think you own a Camaro! It is a nice car as it appears, but its still a very heavy big car! Mods in my opinion, should be better wheels and tires, sway bars front and rear so it corners flatter.
 

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1968 Cadillac Deville
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Discussion Starter #12
I assume you've inspected the brakes? or have service history on them. Not knowing where in the world you live I can't comment on rust. First thing I do with any older car is establish a baseline for safety. BRAKES, then cooling system then hoses. Then once its deemed safe do I think about mods. Reading what your plans are, it sounds like you think you own a Camaro! It is a nice car as it appears, but its still a very heavy big car! Mods in my opinion, should be better wheels and tires, sway bars front and rear so it corners flatter.
It was not purchased to simply drive. I bought to modify it into the car I have envisioned. I know the main issue is the weight which is why I am leaning towards a LQ9 and not an LS1. The engine and trans comes out of a Silverado so I imagine it should handle the weight.

Just looking at my options.

Thanks for any input.
 

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1968 Coupe Deville, 87 Mustang, 00 Mustang
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149 Posts
Reading what your plans are, it sounds like you think you own a Camaro!
Considering the curb weight of a 68 Coupe Deville is supposed to be 4400 lbs give or take, be careful because the newer camaros weigh in at 3800 lbs and up to 4100-4200 on the ZL1 models.
The challengers also fall into the 4000 range. Thats not far! All that fancy new, quiet, comfortable, expensive stuff is piggly wiggly weight these days.

I also looked really seriously at doing a LY6 6.0 swap with a 4l80 in my 68 Coupe. I nearly had a motor and trans purchased but the friend of a friend, of a friend left me hanging. For now I'm going
to chillax and ride the 472 out for awhile. I don't particularly like removing working drivetrain anyways. I was thinking maybe getting the stance right with airbags might be a more useful mod to do first.
 

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1968 Cadillac Deville
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Discussion Starter #15
Considering the curb weight of a 68 Coupe Deville is supposed to be 4400 lbs give or take, be careful because the newer camaros weigh in at 3800 lbs and up to 4100-4200 on the ZL1 models.
The challengers also fall into the 4000 range. Thats not far! All that fancy new, quiet, comfortable, expensive stuff is piggly wiggly weight these days.

I also looked really seriously at doing a 6.0 swap with a 4l80 in my 68 Coupe. I nearly had a motor and trans purchased but the friend of a friend, of a friend left me hanging. For now I'm going
to chillax and ride the 472 out for awhile. I don't particularly like removing working drivetrain anyways. I was thinking maybe getting the stance right with airbags might be a more useful mod to do first.
When you concidered doing this, what did you find to be the biggest complication. I have seen more then my share of Caddy Coupes with LS1 engines. Before I buy the engine I am hoping to hear from someone who has done the swap.

I don't feel the 472 would be a step down just a different type of ride.
 
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