Caddy 500 Cu Inch

chromebumpers

solid fixture here in the forum
Staff member
How much are they worth? Runs, comes complete with everything even headers. Currently running in a 73 pickup. Doesn’t smoke, no bearing noise. Can hear it run then will pull.
 

rlphvac

solid fixture here in the forum
Rich you didn't include the year of the motor I would want to know this if I was looking for one
 

chromebumpers

solid fixture here in the forum
Staff member
I never got an answer about the caddy 500 Cu in. The info I get is the 68 to 73 engines are the better ones? Value?
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
price varies by year appearance and external condition, accessories like intake or exhaust manifolds, motor mounts flex plate etc.
but if you find one 475-570 is the going range at a u=pull-it last time I checked
that comes with a guarantee, it has no major problems
(IE the block, crank and heads are in rebuildable condition)

and can be rebuilt by a competent machine shop,
if your wallet will stop screaming
components like the pistons rods,water pump, oil pump,cam and lifters are considered throw away and replace parts,
and yeah the block might need a bore/hone and the crank may need to be cut and polished undersize on a journal or two.
 
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chromebumpers

solid fixture here in the forum
Staff member
I have a work up bid to break it down, clean and all machine work for $2,500. That seems high. It comes with every bit of hardware and all accessories but another car to put it in, right now it’s running and in a 1973 pickup truck. I really don’t have anything left to put it in, down to my last three cars and they’re here only because I haven’t put them out there yet.
I thought I had time. Another guy bought the truck, but my condition to his price was to let me have some time to remove the motor or sell it from the running truck. I sold my Northern Eq. Engine stand otherwise . . . .
Unless I find something for this 500, I’ll have to sell it. I can’t get past the idea that putting it anything makes a Frankenstein mobile.

Last year I had a 74 Trans Am roller, but I can’t see a Pontiac w/out a Pontiac engine for obvious reasons unless it’s on a Road Kill show. :eek:
 

chromebumpers

solid fixture here in the forum
Staff member
I have Motor Manuals 1964-68 and 1971-77, missing 69 and 70.

Caddy 500 Cu motors for 1971 were rated at
365 hp @ 4400 rpm and 585 Ft lbs @ 2800 rpm with 8.5 compression.

The 1973 motor is rated 235 hp @ 3800 rpm and 385 ft lbs@ 2400 rpm

I’m curious that the compression ratios remain the same 8.5 in all 500 Cu inch motors. So what changed the power so much?
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
the caddy v8 cylinder heads pistons and valve sizes changed several times, and in many cases are at least in theory interchangeable to some extent,
it is possible to get up to 11:1 compression changing / mis matching years on different various components

https://www.cad500parts.com/catalog/index.htm

https://www.cad500parts.com/catalog/page17.htm

https://www.tpocr.com/cadillacec.html

https://www.vindecoderz.com/EN/Cadillac

https://vincheck.info/free-vin-decoder/free-cadillac-vin-decoder

http://garage.grumpysperformance.co...a-472-500-caddy-engine-in-a-z.862/#post-61163

https://www.cad500parts.com/catalog/page2.htm

https://www.cad500parts.com/tech/EngineIDPages.pdf
Only way to know for sure is to look at casting number in the crank which requires the oil pan to be off or measure the stroke by sticking something down a spark plug hole and hand cranking the engine.

70-76 the block casting ended in 5200 for both the 472 and 500. 70-74 500's only came in Eldos so if its got the oil pan with the rear sump, notch in it, and 2 drain plugs it could be a 500. The rest of the cars got the 472 and had the oil sump in the front (which would be backwards from a more typical engine like a Chevy. 75-76 all cars but the Seville got 500's. The Eldorado pan is the closest to a typical GM setup and over the years the Cad motors have been popular to swap into other cars and trucks so its possible that was what someone had done or planned to do with this motor so it could be a 472,500,425, or 368 with an Eldorado pan. Its also possible that an original engine was replaced with what ever was available at the time.

500 has roughly a 4.3 stoke, 472 roughly 4.0 so you are looking for around a 1/4" difference.

Block casting number is on the top leftish side of the flange where it butts to the transmission.
About where the distributor would be on a Chevy.

1486238 was block casting number 68-69
1485200 was 70-76
1609110 was 77-79 425
1615255 was the 80-81 368 4bbl
1620734 was the 80-81 368 DEFI (including the 8-6-4)

1482464 was the 68-74 472 crank
1495094 was the 70 500 crank
1496793 was the 71-76 500 crank
1609142 was the 368 & 425 crank (same 4" stroke as the 472, smaller and tiny bores)

If nothing has been swapped around there are some visual clues to the year. They changed small things like valve covers and the breathers over the years. EGR started in 73. HEI distributor on some 74 and for sure 75. Electric choke started in 75. Intake was single plane and aluminum on the 425's and 368's. Timing cover slightly different on 425 / 368 vs the 472 / 500.

Picture of the intake carb pad, choke, and egr will narrow down the year. If you have the heads off the type of pistons could narrow it down. Head number can also narrow it down. Head casting numbers are on on the top side center on the smog rail which is between the rocker arms.

1486250 was the 68-70 small chamber smog
1495950 was the 70 small chamber non smog
1497902 was the 71-73 small chamber smog
6024493 was the 74-76 large chamber smog
6024552 was the 74-76 large chamber non smog

The small chamber heads were for the high compression engines. In 71 when GM mandated lower compression their fix was to put huge dishes in the pistons which was less than ideal for performance and emissions. Guessing they were hoping they would be allowed to return to high compression but when that did not look like it was going to happen they re designed the heads to use a more typical piston. Except for the 70 the difference in smog and non smog heads is just if the passage was drilled.

Only difference between a 472 and 500 is the crank and pistons. Everything else was the same including the firing order. Depending on the year there could have been differences like the oil pan if it was in a Eldo or a RWD car.

What is different about the 472-500-425-368 family was the #1 cylinder is on the right side, not the left like many other GM's. The firing order is also not the same as many of the other GM's of the era. I think the firing order is the same as the current LS engines. Supposedly some of the designers of this engine went on to Ford to do the 460 so the 460 has some similarities to the 472 family.
 
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chromebumpers

solid fixture here in the forum
Staff member
I think it was the early Chevy Monza, circa 1980 that GM built to accommodate a rotary engine that is very wide, makes a great candidate for a Frankenstein marriage. I know the Caddy motor isn’t wide but gives lots of room for twin turbos :eek:
 
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