[davesdeville]

I used to have a 75 Sedan DeVille, but I sold that to my grandmother who needed a good car to get to the church/hospital/whatever. With the money, I bought a 78 Fleetwood Brougham D'Elegance. I am pretty sure I can trade the 78 for the 75 because grandma would like the interior of the 78. But, I'm not sure I want to trade. Help me make up my mind.

Which car should I get/keep?
75 - 8.2L 500cid V8, 130" wheelbase, 231" Long, 80" Wide, cloth seats, radio broken.
78 - 7.0L 425cid V8, 122" wheelbase, 222" Long, 76.5" Wide, the seats are like a pillowtop and are very luxurious, and a Sony casette deck.

The 78 is around 900 pounds lighter, and I could swap in a 500ci without too much trouble I assume (eventually when I get some cash, like a year ), and then I could have a nice, big car with excellant interior and excellant performance. Or I could get the 75 with the stock 500 and I could have a huge mofo car with a pretty nice interior and pretty decent performance.

A really dark pic of the 78s interior was attached to this post, but it was too dark to be worth posting.

 

[HotRodSaint]

Do what Grandma wants. You will be happy either way. So making Grandma happy is the key here.

 

[davesdeville]

She says she doesn't care, as long as she has a Cadillac.

 

[Mad'lac]

I say tick off MMNine and keep the bigger car

 

[MMNineInchNails]

I'd go fleetwood. It looks a lot better, and with your engine swap you'll be mass pimpin'.

 

[Mad'lac]

Isn't the Fleetwood the shorter of the 2? lol Well you don't need to do any swap with the Deville. Either way they both good cars to have.

 

[JerseyGirl]

Fleetwood!

 

[MMNineInchNails]

Isn't the Fleetwood the shorter of the 2? lol Well you don't need to do any swap with the Deville. Either way they both good cars to have.

yeah, but he said either way he'll eventually swap in a 500, so it's basically going by looks now and interior, not power.

 

[Elvis]

I'd go with the 78. I wouldn't swap out the 425. You can still get a lot out of that block--just because 500 is a bigger number doesn't necessarily mean that it's going to go any faster. Maybe a little more torque, but it's still basically the same engine as the rest.

Now, if you were planning a lot of "show" type modifications, I'd recommend the '75. But since you're more interested in performance and comfort, stick with the '78.

 

[MMNineInchNails]

I'd go with the 78. I wouldn't swap out the 425. You can still get a lot out of that block--just because 500 is a bigger number doesn't necessarily mean that it's going to go any faster. Maybe a little more torque, but it's still basically the same engine as the rest.

Now, if you were planning a lot of "show" type modifications, I'd recommend the '75. But since you're more interested in performance and comfort, stick with the '78.

that is a great point right there. Seeing how my 472 has 375 hp and your 500 has 190hp. 500 has way too much smog shit.

 

[davesdeville]

The 425 is a pretty good engine. The 425 in the fleetwood isn't in very good condition though, which is why I'm thinking I'll keep the fleetwood so grandmother won't have anything to really worry about. I could take the 425 out, fix it or rebuild it, and put it back in, but that would take me quite awhile. So I'd rather get a 500 or 472, get it working well and then swap it with the 425 in a few days. Also if I ever have some money and I want to put a nitrous system on it, a 500or 472 can handle it, but I wouldn't risk it with a 425.

MMNine, your 1970 472 has 375hp and 525 torque, but if you check the same year 500, it has 400hp and 550 torque. A 500 will have the most potential for power, so it's my top choice. There were around 750k Cads made with 500s in them so it shouldn't be too hard to find one, and if I don't get a 500, there were about 1.5 million 472s.

 

[Mad'lac]

Ok since you added the part about the 425 not being in good condition, I say give Grandma the Deville. She'll still have a bigger car than MMNine lol

 

[davesdeville]

I went outside and snapped a couple pics of the Fleetwood, they're up at cardomain.com/id/davesfleetwood.

2 pics of the Deville are up at cardomain.com/id/davesdeville.

 

[Elvis]

HP figures on cars from the mid-70's are misleading. The BHP numbers and SAE numbers are usually far apart.

The SAE method eventually became the industry standard, but then you run into a similar conflict today between the HP generated at the flywheel and what actually makes it to the wheels.

For example, my little Honda supposedly generates 200hp at the flywheel. But a dyno won't show but 150hp. So I lose 25% due to an inefficient FWD transmission. And of course, since it's a 4-banger, there's hardly any torque to mention.

Auto manufacturers will always be able to play games with the numbers to inflate their claims and make things look better than they are. (The bean counters taught them that in the 70's)

I think that you would be better off getting the 425 re-built. It's a lot better than you realize. Same block, smaller bore and shorter stroke.

The TH350 and TH400 transmissions are solid performers, too. That's another reason to consider the '78 over the '75--go with the newer transmission. Two other factors--better mileage and lighter weight.

 

[davesdeville]

Please explain to me (slowly) why the 425 would be better than a 500/472. I'm not getting it, the 425 has a weaker crankshaft and slightly weaker block than the other 2. Unless you're talking about gas mileage or something.

And in 73 the measurements switched to net rather than gross. Net is measured with all accessories attached and off, full exhaust and intake systems attached. Gross measurements are generally much higher, but vary because of the differant methods the testers used. Am I mostly right here?

The 75 Deville uses the TH400 as far as I know, and I was thinking the 78 uses the TH400 too. Anyone know if that's true or not?

 

[MMNineInchNails]

when i said the 500 had 190hp, i ment in your '75, not in a '70 because it was either the '75 deville or '78 eldo.

I'm pretty sure they've both got the th400 tranny, it's a VERY common tranny. They use it in trucks and jeeps. Very strong tranny, that's why they're in offroad vehicles

mad'lac, you're really liking this whole length battle, aren't you? haha.

 

[Mad'lac]

lol well yeah!!! Seeing how I got no chance in it. Might as well be a fan.

 

[MMNineInchNails]

lol. BATTLE IT OUT BETWEEN 6 INCHES. BOOYA! PURE EXCITEMENT!!!

 

[Elvis]

Please explain to me (slowly) why the 425 would be better than a 500/472. I'm not getting it, the 425 has a weaker crankshaft and slightly weaker block than the other 2.

You probably know something I don't. I wasn't aware that the block was weaker. If you're going to tow boats or horses, then I'd say yeah, make the extra effort and put the 500/472 in there.

Of course, I'm not saying there's anything at all WRONG with the 500 or 472, it just seems like you'd be spending more money and effort than you would with the 425 and I'm not sure it would be worth it to me.

And call me crazy, but I'd rather have an Olds 425/455 than a Caddy 390/425/472/500 (I think these were all basically the same).

...but that's probably another debate altogether....

 

[davesdeville]

Actually, my extended family says they'll all chip in and buy a tow bar for Christmas if I give them all my cell # and say I'll tow them if they need it and if I can. The 425 puts out 320 pounds of torque nett which I was told would be about 440 gross, and that's probably enough to do some towing. A good 500 will give me 400+ nett, so it's yet another reason to swap one in. My parents have a little trailered boat that gives moms Volvo some real trouble climbing a hill. So maybe I can convince them to give me money for this....