What would you get - can it be done: 425 block with a 472 crank

dave brode

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425 and 472 stroke is same.

Iirc, at least one of the S/S GT racers [old engines in newer body] ran 472 cranks in the 425 because the 425 cranks were flexing.
Afaik, there should be nothing required except maybe a balance job.
 

Cad Man

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425 head flow with larger valves..
As I've said before there is very little difference between the 425 heads flow wise and the 120's. Even when ported. Not so with 76cc heads

425 head 2.11 dia. 45 deg seat 425 head 2.125 dia. 45 deg seat

12 deg BA 10 deg BA

.100 93 .100 99

.200 166 .200 170.2

.300 208.5 .300 215.5

.400 239 .400 245

.450 246.6 .450 250.3

.500 260.5 .500 267

.550 268.8 .550 273

.600 274 .600 279

.700 261 .700 270.5
 
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Darius

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425 head flow with larger valves..
As I've said before there is very little difference between the 425 heads flow wise and the 120's. Even when ported. Not so with 76cc heads

425 head 2.11 dia. 45 deg seat 425 head 2.125 dia. 45 deg seat

12 deg BA 10 deg BA

.100 93 .100 99

.200 166 .200 170.2

.300 208.5 .300 215.5

.400 239 .400 245

.450 246.6 .450 250.3

.500 260.5 .500 267

.550 268.8 .550 273

.600 274 .600 279

.700 261 .700 270.5
What is this: (12 deg BA 10 deg BA)?? I'm new here.

bro. H
 

Cad Man

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I cut and pasted those numbers from Walker's post..

12 degrees Back angle on the valve
10 degrees back angle on the valve

full ported 120 heads with 2.11 valves basically show the same numbers. If you really push them with bigger 2.14 valves they may hit 290.

Your not new anywhere "D"
 
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Roy Heisenberg

The 472 Crank is stronger due to overlap
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What vehicle(s) do you drive?
472 Caddy in a ‘75 Jeep J-20 TH-400 Dana-60 100LL
So, anyone have a good 500 Caddy block in California or Nevada that they can sell me?

Thanks, Harmon
 

Roy Heisenberg

The 472 Crank is stronger due to overlap
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What vehicle(s) do you drive?
472 Caddy in a ‘75 Jeep J-20 TH-400 Dana-60 100LL
Oops....

Noobie made a mistake and tried to highjack the thread.

Sorry.

I will now switch to decaf,
Roy
 

El Diablo

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1959 Cadillac Sedan deVille
Taking the stock bore "425" block to the machine shop tomorrow along with a set of "472" rods - crank - good used "472" pistons.

Going to see what can be done.
Trying to build with what I already have to keep costs down.
Have a cast iron ported manifold I ported several years ago and will be using it along with a set of stock cast iron "472" exhaust manifolds.
Already have a brand new stock spec. cam - timing cover - chrome taller valve covers - water pump - Eldorado pan & pickup- flywheel eca. eca..
Thinking the biggest cost with this build will be the machine work and maybe a valve train upgrade (not sure about that yet).
Not trying to build anything wild just a good solid low rpm everyday torque engine!
Any progress with this?

I have my 425 in the machine shop as well getting the cylinders bored out and the 500 main caps line bored / honed. I picked up some ARP studs and main girdle from CadCo so it should live peacefully if I don't push it too hard.
 

Roy Heisenberg

The 472 Crank is stronger due to overlap
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What vehicle(s) do you drive?
472 Caddy in a ‘75 Jeep J-20 TH-400 Dana-60 100LL
So wait, are the 500 main caps stronger?

Thanks,
Roy
 

Cadillac Kid 1

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To help with overall weight reduction they took seemingly ever ounce of cast iron out of the 425 motor that they could. I might be a little concerned regarding the cylinder wall thickness if you are talking about boring the 4.005 bore out to 4.30./ Again, this is just my suspicion.
Roy, the 5200 block main caps have more iron to them than do the 425's, but with all the material they took out of the web I would not think adding the heavier caps would do much.
 

El Diablo

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Someone on here posted some pictures a while back of the difference between the 425 caps and the 472/500. I also posted up a picture on the Fb page. It is a huge difference.

I'm really interested in what the original poster is going to come up with and maybe we can compare notes with one another.

I'm gonna find out how a 425 likes a hydraulic roller cam.
 

Darius

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Someone on here posted some pictures a while back of the difference between the 425 caps and the 472/500. I also posted up a picture on the Fb page. It is a huge difference.

I'm really interested in what the original poster is going to come up with and maybe we can compare notes with one another.

I'm gonna find out how a 425 likes a hydraulic roller cam.
That sounds like you are interested in spinning that sucker to the higher numbers. Is that correct?

bro. d
 

El Diablo

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Maybe Bugzaper will. As for me, I'm a more conservative person when it comes to the automotive enthusiast hobby. :sneaky::devil::p
 
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