is the caddy intake for the 425 the same as the 475/500? (i heard there difrent)

I might bealbe to get a 425 for free or dirt cheap and thought it would be a good engine for the scout. It needs some TLC thow

I *think* that some 425's had a higher base for the carb that the 472/500 intake, which was actually lower than the ports on the heads. And that they can be cleaned up for decent performance. My (virtually dead) brain cells are telling me it's aluminum too, but I betcha I'm wrong there.

But they are interchangable in basically every respect. I've got 425 heads on my 472, with the BB Caddy Edelbrock intake. The only iffy thing would be the air conditioning compressor.

--Rob

They are different .. what manifold do you have and what manifold are you looking for??

Pretty sure that the 425, 472, and 500 are the same, the difference being in the bore and stroke.

Originally posted by hy_desert_4wheeler
They are different .. what manifold do you have and what manifold are you looking for??

factory to aftermarket

I heard somthing that the 425 is single plane and the 475/500 are difrent and sit lower but that does not mean that they still bolt up

from edelbrock web site
"PERFORMER CADILLAC (Idle-5500 rpm)


This Performer is designed for 1968-76 Cadillac 472 and 500 cubic inch engines. For either square- or spread-bore carbs, #2115 is the first intake designed specifically for high-performance Cadillacs using standard heads. Like all Edelbrock Performers, this manifold increases torque and horsepower from idle to 5500 rpm. The broad power band is ideal for high-performance street and engine swap applications. Specs on this non-EGR manifold include a carb pad height that's 3" taller than stock. Dropped divider wall evens air/fuel ratio throughout the rpm range. Stock air conditioning compressor will not fit."



does not sya anything for the 425 :confused: http://www.edelbrock.com/automotive/autopartsphotos/manifolds/2115.jpg

The 425 intake is a cast iron, single plane manifold.

The 472 and 500 intake is a cast iron, dual plane manifold.

I have a 425 caddy temporarily in my 76 chevy, until I get my 513 Caddy back in. Its a dog, they never made much hp in stock form, and its quite apparent. Its better than any stock SBC that Ive ever had, but still nothing like the stock 472's and 500's that Ive had.

Dont bother putting any money into a worn out 425 Caddy. Even if its free. You should be able to find plenty of 472's for cheep to free, once you kind of get into the caddy "mode". When I started out with caddys, I couldnt hardly find anyone that could even identify them. But now people call me, trying to unload their "Junk" all the time.

IMHO Stock rebuild Caddy, with a mild cam and headders is perfect for wheelin large rigs.

thanks


hmmm thers a 472 sitting in the school MX class maybe I can get my hands on it.

The 425 I have is MPI and seems to have more power than the Oldsmobile 455 that I used before it.. The reason I ask which manifold you had is I thought you might have the MPI and be looking for the 4bbl..

Originally posted by hy_desert_4wheeler
The 425 I have is MPI and seems to have more power than the Oldsmobile 455 that I used before it.. The reason I ask which manifold you had is I thought you might have the MPI and be looking for the 4bbl..

no its just a 4bb


the engine had an oil pump isure but it had low miels, so I think i'll use it untill I find a 472, then I can swap the 425 heads on the 472 and run the slug on propane

do I have to get new valves and seats for thies engins to burn propane or dont bother?

Originally posted by Chief yelling alot


do I have to get new valves and seats for thies engins to burn propane or dont bother?

The general answer is don't bother, but Caddy may be a little different.

One thing to consider, what is your compersion ratio going to be???
Propane is happy at 11:1...

[i]Originally posted by Chief yelling alot

do I have to get new valves and seats for thies engins to burn propane or dont bother? [/B][/QUOTE]

You dont need to worry about the valves in the 425 heads because they have the hardened seats from the factory..

Originally posted by That Mick


The general answer is don't bother, but Caddy may be a little different.

One thing to consider, what is your compersion ratio going to be???
Propane is happy at 11:1...

well eaven stock CR is good enugh if its tuned rite, the caddy stock CR is about 8.5 IIRC the 472/425 head swap puts it about 9.5 CR so that should make up for any power loss (if any)


thanks guys

Originally posted by Chief yelling alot


well eaven stock CR is good enugh if its tuned rite, the caddy stock CR is about 8.5 IIRC the 472/425 head swap puts it about 9.5 CR so that should make up for any power loss (if any)


thanks guys

There will be some power loss as compared to gasoline, because propane has fewer BTU's than an equal amount of gasoline.

The 9.5 CR and propane will have about the same power as the 8.5 and gas.
No power gain, but works better at an angle, cheaper in Canda, I guess.

Originally posted by That Mick


cheaper in Canda, I guess.

yup .37 a leter the other day

:eek: :eek: the gas bill on that engine would kill my bank if i burnt regular