500 caddy or 455 olds?

[ratty69]

Which one should I get?

I found a guy selling one of each. A 75 rwd 500, and a 73 455 from a 98 that will become derby cars. Either will come complete air cleaner to pan, fan to yoke and wiring. Neither has smog stuff. I've heard the caddy run long enough to drain the carb, and it sounds good. Trans wouldn't go in gear, fluid too low? Olds not running yet, but he will make it run and let me hear it.


So the caddy is cheaper upfront, but will need more parts/work to fit in my truck. The Olds should just drop right in once the frame stands are moved to the right spot.


So, assuming both run equally well, which one would you get and why? Please don't suggest LS, not happening for many reasons.


Thanks for reading.

[mike16]

500 caddy

[Killer Bee]

Dr. Oldsmobile says....

not sure what's out there for big block cad aftermarket, but used to be lots of stuff for the olds..

good luck either way!

[clay68c10]

Caddy! Plenty of parts available.

https://cadillachighperformance.com/

http://www.cad500parts.com/

[1972RedNeck]

500 Caddy all day...

[71cadc10]

if they both run equally well....same price...here would be my opinion

more displacement, and torque = Cad wins
lighter weight = cad wins
trans/convertor bolt pattern = both are same = tie (both are different than chevy)
fitment to truck = Olds may have advantage (rear sump pan needed for caddy). If you can find a rear sump caddy pan, then it would be relatively simple to put the cad in there I believe. They are both very wide units LOL

[Steeveedee]

Are you getting either engine after the derby is over? It's likely to be toast after a crash that destroys the radiator and the crowd wants to see the thing roll to a stop in a cloud of smoke. I'd want to hear it run after the wreck.

[68Gold/white]

Plan on putting one in your pickup??? I'm guessing?

I believe the Cad engine is physically somewhat larger, may or may not be problem in pickup install.

Either would be good...

[dozerbill72]

Caddy for sure. Put one in a 49 GMC 30 years ago had the power to pull anything and didn't get horrible milage either.

[ratty69]

Originally Posted by Steeveedee

Are you getting either engine after the derby is over?

Nope! He sells off the original powertrains and installs an sbc or ls for the derby; he said they run about 20 minutes without water. After they cool again they start right up.

[RustyBucket]

Originally Posted by dozerbill72

Caddy for sure. Put one in a 49 GMC 30 years ago had the power to pull anything and didn't get horrible milage either.

I put a '72 455 Olds in a '79 short Silverado and it was AMAZING how much gas it burned. Serious tire burner too.

[ratty69]

Thanks for the replies, everyone! Looks like I'm getting the caddy...

[ratty69]

Originally Posted by RustyBucket

I put a '72 455 Olds in a '79 short Silverado and it was AMAZING how much gas it burned...

Definitely don't want that with todays gas prices!

[Steeveedee]

Originally Posted by ratty69

Nope! He sells off the original power trains and installs an sbc or ls for the derby; he said they run about 20 minutes without water. After they cool again they start right up.

Does he use that engine oil that doesn't let the engine overheat after hours of driving? Are LS engines that cheap?! Man, I ought to get one for my truck.

The only experience I have with an engine locking up is way back in the mists of time (about '71) when one of my little sisters wrecked her '62 Nova convertible (45 minutes after getting her license!). We went to get another Nova with a rod knock and proceeded to drive it home (35 miles!). It got louder and louder as we drove, and it finally threw a rod, with that piston exiting the side of the block. I just kept driving it until it seized. Then my mom took me home to get the tow bar. My younger brother (who did not have a license at the time, but it was on a dirt road) had stayed with the car to keep it from getting impounded while we were gone. When we got back, it was about half a mile closer to home, because once it cooled off, it would run again. Tough little I6 Chevy. Fun fact- my dad asked me why I didn't just pull the plug wire off the affected cylinder. I was thunderstruck. We would have made it home with a lot less trouble, but I just hadn't thought of it.

[ratty69]

Cool story! And yes, Chevys are tough! I've never managed to seize an engine, I take pity on it and shut down before that happens.

That derby guy did show me his current car - ls powered. He said he had the ecm reprogrammed to compensate for overheating - fuel and spark curves adjust to help it run cooler. Idk the specifics, but I think the hotter it gets the richer it goes.

Computers aren't my thing, that's why I want an old school big block.

[weq92f]

T.
.
Def the 500 Caddy!

Top it off with one of the available EFI systems and don't look back!!!!!!!

-klb

[bw46]

I would go for the big block Chevy.

[mike16]

Pontiac, 428.....

[Killer Bee]

^ yes! Poncho power

[ratty69]

Originally Posted by Killer Bee

^ yes! Poncho power

I agree. I looked for a Pontiac engine first, but they're unobtainium around here. And when you do find them, they're usually a 557 block 400...

[68C15]

Longhornman did a writeup on stuffing a big cad in our trucks.

Dimple (sister sledge) the driver firewall.
Rear sump pan and pickup tube
Square body towers and cad mounts.


Just use a light foot in winter. The big caddy makes big torque, NOW!

[pat english]

If I cold get both,I would do that.They're both bop bell housing pattern.you could have one In your truck tearing it up,and one on a stand waiting to drop in.

[pat english]

If you want a 4 speed though,I think old's is the way to go.caddys are only automatics.

[cypressbog]

Originally Posted by 68C15

Longhornman did a writeup on stuffing a big cad in our trucks.

Dimple (sister sledge) the driver firewall.
Rear sump pan and pickup tube
Square body towers and cad mounts.


Just use a light foot in winter. The big caddy makes big torque, NOW!

Yep. Couple other members use the 472/500 Caddie powerplant. I also recommend Caddie over 455.

[Steeveedee]

Originally Posted by pat english

If you want a 4 speed though,I think old's is the way to go.caddys are only automatics.

I know that one could get a manual four speed in a Calais coupe, back in the late '60s and early '70s. RARE. All the BOP bell housing and clutch parts will fit. That would be a pretty cool ride!