Hey have this "71 cadilac hearse and took out the motor and cant seem to identify it. Looked for the cast number on the driver side block an didnt find it found a cast number on the left 1495200. Could you tell me what engine this is?
I am unaware of a way to tell the difference between the 472 and the 500 by looking at the exterior of the motor. I've been told that the only sure way is to pull a head and measure the stroke as you turn the crank.
These guys may be able to tell you a way. Scroll down a little, their phone number is on the left of the page. Index
But i read both 472 and the 500 got the same cast number does the imprint engine number offer any help. 610150455 imprinted number an cast number is 1495200
Yea, you're right, I just looked in my Cadillac book, I'll keep looking for a definate way.Better yet, call Marty at MTS, if anyone knows he will.....(760) 247-2533
They sure will but....... the '68-'73, 76cc heads have a better combustion chamber and no air tube cast in, the problem lies when bolting them onto a '74-'76 engine that has the soap dish piston designed for the 120 cc head. You end up with "around" 13:1 compression. If you're building a full on performance or race engine a change to the proper forged pistons will be in order.
I ported my 120 cc heads and had new guides and larger 2.11/1.77 Pontiac stainless valves installed. After surfacing the block and heads the compression came out to 8:7 to 1 which is perfrect for the chitty gas we have to run. Dyno'd 466 hp @ 5k and 535 torque @ 4300....plenty for me.
Sorry, but I never get tired of posting these pics, please humor me by the way the red line is the torque curve........which in reality isn't much of a curve.
Why we like our cads.. we get lots of usable power from a mild build..
the difference in 472 and 500 cad is in the stroke. I fit is out of the car all you can do is pull a head and measure it.. If it is coming out of a known car then we can assume it is either a 425 or 472 or 500..On mine all I am going to do is a good re-build with a mild cam and the good valve train as I will plenty of power for a light roadster..
As a general rule of thumb rear wheel drive cars up to about 75 had the 472. They saved the 500's for the front wheeled cars.
Another easy way to tell is by pulling the oil pan and checking the crank. A 472 has 424 stamped on the weight towards the front and a 500 has 94 or 74 towards the rear. Of course this only works in a stock appplication.
If all this fails there is one other way before pulling the heads.
Math
472= 7.73L/8=.96625L per cylinder
500=8.2L/8=1.025L per cylinder
Pull the the manifolds off then rotate the engine until one of the cylinders is at the bottom of the stroke. Rotate the engine until the cylinder is flat. Measure 1.025 liter of oil out and then pour it down the exhaust of the cylinder somewhat quickly without spilling. If it stays in it is a 500 if it pours out it is a 472. Then just flip the engine and crank it to move the oil out before putting the heads back on.
It is about 20 oz difference and enough to tell even if the rings are a bit worn.
One way to be sure of the engine displacement is to measure the stroke. The 500s have a 4.300" stroke and the 472 have a 4.060" stroke. The 425 and the 472 have the same stroke so this method will only distinguish the two from the 500. First remove one of the spark plugs and turn the crank until the engine is at top dead center. Use a piece of stiff wire or something similar for the measurement. What you want to do is take a measurement at top bead center then a second measurement at bottom dead center. The 425 and 472 will have a 4 1/16-inch stroke. The 500s are closer to 5 5/16 or 4.304 inches. This makes the 472’s compression height about .110 higher than the 500. The 500's stroke is about 1/4 inches longer than the 472.
From the Caddy Shack
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