If so what are your thoughts on these engines?
Feedback will be appreciated
Thanks

Talk to Brook, he is on this site occasionally, Bgreen i think is his handel. I personally was looking into it, but decided to go SBC 400. Nevertheless, Brook has all the info you will need, an he has a hardcore rig with the monster caddy. His email is bgreen@alaskaoffroad.com. Also, check his site out at http://www.alaskaoffroad.com/. He has alot of info about the caddy there as well.

Heya James. This site has a couple of guys who've made the switch.

www.67-72chevytrucks.com

Just post asking about it or do a search. The guys who've tried it love it.

These guys have a pretty good forum for tech and swap talk:
http://www.500cid.com/frames.html

And these guys have a great cataloque of parts that include some tech articles. (it's free too!).
http://www.cad500parts.com/

I'm thinking of making the switch too but I don't have the funds for the mounting brackets and special caddy (ie more expensive) headers and so on that I'd need or want to put one in my '69 Chevy. Are you putting it in a 4X4 or a 2WD. Apparently the swap into a 2WD Chev is actually easier in a lot of ways than a 454 swap though I don't know about a 4WD Chev. I did a bunch of looking into these things until I lucked into a great deal on a 454. I might be able to answer a question or 2 as well about where to find info and so on. A fully equipped Caddy 500 only weighs around 50lbs more than an all iron Chev 350, it's more narrow than a 454, it's supposedly more durable than a Chevy Rat because of the higher nickly content (also why it's so light) and there are a bunch of speed parts from other engines that can be adapted to fit. The problems are that not too many companies make parts specifically for the Cadillac engines so parts can be expensive, the valvetrain isn't really meant to take RPMs above 4500, and they need some machining to mate to a 4-speed.

You've probably read all of that already, though, so I'll shut up!

Greg

(BTW if anyone out there has a Caddy 500 that's in decent shape and complete and they want a complete 454, PM me, I might be interested).

i know of a 69 caddy 4door with a 472 runs great!

hmmmm.....'69 472. I haven't looked it up for awhile but I think that's a pretty good year; pre-smog which means good heads and a decent intake and I think all that's involved in making it a 500 is a different crank.

The other thing about the Caddy's is that the TH400 they come with is supposed to be extra stout.

Greg

Well if your looking for a Caddy.. You have a couple of choices, either look for the early 69-72, with the 472, all that needs to be changed is the crank and pistons to make the 500, if your looking at rebuilding anyway.. It's an options, this engine comes stock with 11.5:1 compression, and small chamber heads. It is also a non smog block..

The actual 500 Caddy's are from about 71 to 75 I believe, they run 9.5:1 comp stock, on average. Everything between the 472 and 500 are interchangable. But watch out for the 425, they look the same, but nothing is swappable.

As for engine mounts, if your pulling the engine, just pull the engine mounts out of the caddy as well.. You may as well just relocate your mounts to fit the engine, it's easier and cheaper than forking out the $200 for the aftermarket ones..

Headers are a bitch, BUT, Hedman, and Hooker both make a wonderful set $500, bolt right on..

As for a tranny, plan on using an automatic, as I have not found a Caddy with a stick, and no one seems to make an adapter for a SM420.. *My personal choice anyway* I talked to Advanced, and a couple other places, they all thought it was a hell of an idea, but didn't make anything..

Steve
www.ccr4x4.com

I'm in the process of building one for my beast.. 400 horse from a 350 just isn't enough..

here's some good info. I'm working on that hooking up a 4-speed idea. I know I've seen it discussed, I just don't remember which webpage it was on. http://500cid.com/mts/AL/article1.html

Greg

(looks like their chatroom is members only now. I haven;t checked out what it takes to become a member but I might get signed back in there)

Thanks for all the info guys it's helped alot. I have two more questions which motor gets better gas mileage a 454 or a 500 Cadillac? and can a 500 Caddy be converted to propane?

If you're planning on running either of those 2 motors, you best be tossing the notion of gas milage straight out the window. They're both pigs.

Well think of it this way, if your truck is going to be less than 6000lbs like the old caddy's you'll get better gas milage, if it weighs more, you'll get less..

You'll see anywhere from 18-22 mpg out of a 500..

But, you would never consider 44" tires, and 1ton power train for a "economical" vehicle anyway..

I think most of the guys who've made the switch say they get better mileage (which is kind of a laugh when talking about 500 ci motors but then again, it's yet another reason I was tempted to look into them).

I think any gas engine can be run on propane.

Greg

A caddy 500 into a rig that weighs less that 6000lbs . Maybe the 500 gets marginally better gas milage, but theres no way it's 18-22mpg. For comparison city driving, most "newer" turbo diesels are in that range, maybe even up to 25mpg. I'd guess more to the 12-14mpg range for the 500, and most 454's I've seen are LUCKY to hit 10mpg.

Yeah I'm debating here what kind of truck to build either a 88 or newer 454 3/4 or 1ton on propane or an 87 or prior 500 Caddy 3/4 or 1ton on propane.

What kind of compression ratio could I safely run in the 500 if it's on propane (it's going to be a daily driver!)?.

I think propane has an insane octane rating of like 110 or something so you could go as high as 12:1 (possibly higher?). Please correct me if I'm wrong because all that's info from asking around and not from firsthand experience so I probably shouldn't really be saying anything at all. It will definitely depend on whether you're planning to go to a dual-fuel system or propane only.I'm pretty sure that with the Cad, it'll probably get much more spendy much sooner than the 454 when you start trying to do stuff like get really high compression. I can't remember offhand what the highest you can get from swapping heads around but I don't think it was all that high. I seem to remember that the bowls on the 425 are just too small to be of much use to a 500 engine; not much room for larger valves and unshrouding them, the diameter of the bowls is a fair bit smaller than the bore of the 500 so there's probably some work needed there. The Cad sounds like a great stock engine but no one ever meant it as a muscle car/truck engine so performance stuff is really pricey even compared to a BB Chev.

I've asked the same question on another board I play on and I think the best answer I got was " Dude...pretty high" which isn't that helpful.

I should shut my mouth now 'cuz I'm definitely talking way beyond my firsthand knowledge of things. I'll just say there are tons of resources on the 'net and in old Hot Rod mags. I'll go look up the issues I have for ya, if you like.

Greg

Ya, use at least an O.H.G. 450 mixer or better on a big block, or dual 425's. Not a single Impco 425, a single 425 will just choke off a BB with lack of fuel.

13:1 is the highest stock swap you can get, I believe that's by putting the small chamber 76cc heads 69-72 472 heads, on a 74 or later 500 block.. This is best for high octane use..

A Cad 472 with 76cc heads, ran a stock 10.5:1 compression, and the 500 ran a 8.5:1 compression with the 120cc..

I'm currently building one, Speed Pro and KB both produce pistons for this swap..

If using a 472 remember that the Crank and Pistons are different, both must be out of the 500..

Steve

Have you looked into a 427 out of a three ton or a school bus? Appearently some of these had tons of power, and you could find one (from a bus) that has been converted to propane already.

I have found some good propane info on this Impco forum:

Impco Tech Talk

Some propane engine building info:

Building a Propane Powered Engine that lasts!

And here is a webpage about a blazer with a 472 cad on propane:

HULK (1983 Chevrolet Blazer) Specifications

I heard a buddy of mine talking about those 427 bus engines and I'm pretty certain I heard him say that they had a pretty deep/tall engine block and were not a practical swap into a car, but I've never even seen one or know anything about them, so I can't say I will not look into it!

Sanderson has headers for about $300 US I think. I bought a set, and can attest to their quality.

OldDog do you or anybody else on here have any info on the 427 bus engines?.

bgreen how do you like the Caddy motor in your truck?

are they not just tall deck versions of the chev 427. heard they are no good to build up. are we talking about the same thing?