Okay since I had a 350 thread up and everyone seem like I shouldn't build a dd sbc I want to start out saying I do not want and can't aford a turnkey boat so I want to build a boat a peice at a time that being said someone did mention to use a caddy 500 for a dd boat with little to no mods that sounds great but I haven't heard of any around here my ? Are what all body styles and year makes cadilacs will have these motors that would help me in my search ....also looking for a hull range size I was wanting a 15 but not now I'm open to opinions I would like to haul at least 3 hopefully 4 people I will be running deep water quite a bit but will be hitting shallow sandy bottom rivers alot I would like it to ru. Dry short distance like pull on sandbar for Lunch ect no hill climbin here but sorry for the long post just trying to take as much info in as I can before decideing on what to build but really like the caddy idea if I can find one
thanks so much
jason

There's others here who know this info by heart... I'm gonna ballpark it, and say you should be looking for an eldorado, fleetwood, coup de ville or other big bad caddy from 1969 to 1974. (maybe a few more models and few more years)

The 472 is the same block as the 500.... it's just a different stroke. I guess you could think of it as the 500 is just a stroked 472. 4 1/8" stroke on the 472???? and 4 3/8" on the 500???? I don't recall the exact numbers, but it's not much of a difference.

I've heard it said that you should be able to buy a motor right out of a car AS-IS for about $200 or $300 or so.
Yes these motors are getting more an more rare. So that price may be creeping up.

Check places that sell core parts to rebuilders. (otherwise known as junkyards LOL)
You can also buy a stock motor rebuilt from Discount auto parts... but that's a higher dollar - but they are ready to install and fire up!

Good luck.

Well I can tell what i have and how it does. I have a 13.5 X 7 foot Laser hull with a 500 cadillac. The only mod I know for sure is an Edelbrock Alum. Intake. I have worked on the Q jet no PCV ( its vented to the prop) 72X36 Sen. prop, Light springs heavy Wts in the HEI dist. I have the timing set at 8-10 init. and will it hit about 30 at WOT, I run Delo 15/40 with STP for the zinc.
The boat will run about 45-50 MPH it will run dry some and by myself with a cooler full it did make it up a pretty good hill
The car you want is a 1970 to 1976 Cadillac Eldorado. Some Coupe Deville had them too. a 472 is hard to tell from a 500. You just about have to measure the stroke.
Its a good boat not bad on gas and for now it works for me. Thats a quick overview.
There is a world of information to be found here. ruagator,Stan,crowhater and bondsman know what they are talking about.
Like I said I can tell what I have learned but thats about all.
I put mine together all told for about $8,000 NOT INCLUDING LABOR
But its been real fun and have met some of the best people in the world here and out and about.
Good Luck and PM me anytime I will help where I can

JASON I HAD LOTS OF $$ IN MY MOTOR AND GOT AS MUCH OUT OF IT I COULD BEING DD
I LOVED IT FOR A RIDE BOAT IF THE NEW CONT. =MOTOR DOESENT DO WHAT I WANT ILL GO BACK TO A DD CADDIE


MODS = RV CAM
CLOYES TIMING CHAIN
GOOD CARB JMO 500 2 BARREL OR 750 VAC.SEC HOLLEY
76CC HEADS AND SOME GOOD OL FEL PRO GASKETS THATS THE CHEAPEST WAY OUT

MY MOTOR HAD 1 PIECE SS VALVES STD SZ PORT AND POLISHED HEADS 120CC BECAUSE OF THE PISTONS I RAN .40 MTS FLAT TOP WITH MTS RODS HIGH VOLUME OIL PUMP STOCK FUEL PUMP WITH ELECTRIC BACK UP STOCK INTAKE FOR DD IS THE WAY TO GO AND HAND BUILT 750 HOLLEY POLISHED CRANK CAD COMPANY RV CAM WITH SPRINGS AND LIFTERS SS HEADERS THE BIGGER THE BETTER LIGHT WEIGHT HARMONIC BALANCER BIG ALT 100 AMP + HEI DIST.WITH A CURV KIT
THATS ALL I CAN THINK OF NOW GOOD LUCK THIS IS SOME IDEAS FOR YA

Oh yeah, DON'T BREAK THE DIPSTICK TUBE!!!
It's NOT a standard item you'd pick up at Auto Zone.

been there done that!

Be careful which model year you buy. If you check wikpedia they have a list of model years and specs of these engines and there is a 200hp difference between a 500 from 1969 to 1976. I have also been able to find a few for around $500. And eventually you will probably want to go to a belt drive or gear box and they start around $2500 plus the changes to your metalworks. There are also some good websites for parts like www.cadillacperformanceparts.com and www.cad500parts.com. Hope this helps.

In your neck of the woods I would also try craigslist as well.. I did a quick search.. Here is a couple from the states close by...
http://columbus.craigslist.org/pts/1589717222.html
http://louisville.craigslist.org/pts/1589512404.html

I didn't see any in WV but I am sure they pop up there.. Just keep a eye on it

If you even think of owning a gear box down the road don't start with a Caddy, unless you are and engine builder like Charles, Bonds, etc. These motors are great for direct drive and by far the most expensive motors to build for a good gear box application. I have close to $10,000.00 in my engine. I was just starting in the airboat world and did not know any better. This hobby is like a cancer and it will eat you up and your wallet. For what I have in my motor I could have a Waterthunder engine, which in my opinion would be twice the engine I have now. Start out with a Chevy engine small or big block. This way you can go to your local parts house and find parts readily available and half the price of a Caddy part. If I wasn't so darn old and could start over this is what I would do. Scott

500 cubic inch engines were standard in 1970 -1976 Eldorados. The 1970-1973 engines are 10-1 and good choices. The 1974-1976 engines are 8-1 and are fine but not quite as powerful, but are less prone to detonation due to the lower compression. You can also run regular gas in them. The 500 was also standard in ALL large body Cadillacs in 1975-1976 i.e. the 472 was no longer offered after 1974. Nothing wrong with a 472 but if you are gonna be a bear, be a grizzly. There are 3 absolutes about a direct drive Cadillac--1)replace the timing chain asap with a good Cloyes unit. 2)do NOT set the timing more than 36 degrees total--get this wrong and you will blow the engine up from detonation 3)run the stock ALUMINUM oil pump and check your pressure religiously and these pumps, especially the melling aftermarket pumps, are famous for the valve sticking and causing zero oil pressure and a burned up engine.
I also advocate losing 40lbs off the transom by using a 2115 Edelbrock aluminum intake. Others claim the original iron does a better job and we agree to disagree on that point. Weight is king in an airboat in my opinion. It is also a terrible mistake to substitute timing pointers from engine to engine since cadillac changed them 5 times over the 8 model years for this block. A mistake here equals destruction. Run the Q jet carb--they are great direct drive carbs. DO NOT build a Cadillac for a geardrive---it was done by me for 15 years and i finally realized the BBC is a much cheaper, more reliable solution.

Regards, Charles

Ditto! Listen to what Charles is telling you!! I personally get tired of saying the same stuff over and over again, some people need to learn the hard way.

I do however disagree about the intakes. The factory intake with a 1" divided spacer works better then the Edelbrock aluminum intake. However if you modify the Edelbrock aluminum intake it will out perform the factory. Weld the plentum divider all the way up and weld the exhaust cross over shut it will out perform the factory intake, the 1" divided spacer works very well on a welded up Edelbrock aluminum intake also. Please remember we are talking direct drive applications!!


My choise for carbs is the factory quad.
Ignition is factory HEI
Cloytes 3* timing chain degreed ahead 3*!


This motor if it is a 10.1 compression 500 cadillac will swing a 72X40-44 paddel prop!

Now I am curious because I have been thinkin of going caddy. If you built one with quality cam components why could you not run one with say a 1.7-1 or a 2-1 belt drive. With the right prop you still would not be turning your motor up too much I would think.

This is how it all starts! Look at my sig and you will see where it takes you.

APACHE14, a 500 Caddy with a few upgrades (cloyes timing chain, 2115 Aluminum intake, ect.) Basically what Ruagatr said. Will run good with a 1.7 gear ratio and the right prop. Just pitch the prop so it wont turn over 4K. A Caddy set up this way will run good and last for years. The problem starts when you start looking for more power and push them past that point. A lot of guys have spent a lot of money chasing HP & TQ and pushing the envelope with Caddys, me included. If this is your goal, Listen to Ruagatr, and crow. Just start with a BBC, it will save you a lot of money. But if you have a DD Caddy, and you want to go to a gearbox, You can do so. But you are better off to stay conservative with it. You have to spend a lot of money to build a Caddy that will run up to 5K and not come apart.

Thanks alot guys for all the replys I think I will go with a caddy what is the biggest size hull I can use with a dd caddy I would like at least 14x7 four seater is this possible also is that possible with a 472 motor..... I was thinking about going ahead and buying that 472 caddy motor posted from craigslist(thanks alot by the way) for 250bucks not bad price if it runs can I use the same timing chain mentioned for a 472 and if so what degree? Also what carb and intake for the 472? Thanks so much guys I am going to get my engine ready the buy a hull to fit the motor then find the rite prop the only bad is I'll have to drive across the country to find a good used hull but thanks agian for your help
Jason

A 14ft boat would be just fine for a Caddy. I would look for one that is wider than 7ft. a 14x7'6" or a 14x8 will be a lot more stable and float that caddy motor real nice. More square inches of bottom surface area. It will ride better and be safer in deeper water, not as tippy. Airboats have a high center of gravity. You would be suprized how much difference there is between a 7ft wide boat and an 8ft wide boat. My first Caddy boat was a 15x8 and it rode like a dream. I bought a 500 Caddy from a junk yard for $500 and ran that motor for a year before I made any upgrades to it. I am not recommending that. you really need to replace the timing chain and a few other things as mentioned in earlier posts. I would call around and look at some junk yards for a 500 motor. It has a longer stroke and will make more TQ than the 472. It will have more power where you need it for a DD application.

Do your wallet a big favor and consider buying a complete rig. You are a very long ways from cheap airboat parts - if they even exist. There's a 15' Rivermaster on here now that is pretty much exactly what you say you want.

That's what I did. Stock caddy 500 motor, I changed the pulleys in my 1.77:1 belt drive to make it a 2:1 drive, and put on a wide blade (2 blade) WaterWalker prop. It's pitched so that when I STAND on the throttle, the motor is turning 4000 rpm. That's 2000 rpm for the prop, and I cruise at about 2800 (engine) & 1400 rpm at the prop. The slower turning prop really ads to a smooth and quiet running boat. I love it, and it's got plenty of power to push the heaviest 18' barge I've ever owned!!!

One good thing about buying a turn-key boat is you get a little vacation out of it. Or at least a road trip. That's always fun!

matt.

I started with a beat-up 15' rivermaster hull had a 472 with a 72lxl38 turn it 2950 WOT. Great starter boat. Mine I could let off the gas in deep water and let it stettle in without any water coming over the back. It was aslo 7'-4" at the gunnel a little tipping in a very slow turn. Almost went swimming once, let off in a turn deep water. Don't really know what's in the motor. I was told RV cam and Cloyes timing chain. Has a 2 brl 500 holley with stock intake. Nothing Special but look at you tube " airboating at the gator shack" grass was wet. It would cross dry but would not run dry. It took a little while to learn how to drive and that seems to be half the battle. As for the motor it has had the crap run out of it. I was able to pull a 14' airgator on plane back to the ramp almost 5 mile.

I definitely want a stinger gearbox one day and if goes on a caddy i'll stay with Plumcrazy idea's with a 1.77 on so box.

I only had the money to take baby steps. Just bought a caddy motor to rebuild, I want to see what a fresh 500 with a few mods can do.

I would definitely listen to the advise above these guy had all been through the caddy school of hard knock.

Mike

Charleston to Orlando FL is under 800 miles and takes about 12 hours according to googlemaps. I think you would save yourself a lot of time and money getting a complete boat. TRUST ME.... you will still build your own

Yep as every one else said...and yes I do have the Cloyes chain.....and the driving thing means a lot too....a good driver can make ya say dang I wish my boat could do that!?!?! and it can its just how you drive it.,....sometimes

Yobee is right too this is really my second boat same motor and some of the same parts but number 2 all together
Just have fun and keep playing with it.

Ive still got the same engine block.... and frog gig.

X2!! Even if it's a basket case and doesn't run.. You will still have all or most of the nickle and dime stuff that will break a person starting from scratch.. IMO Probably the biggest plus is when you build the new rigging how you want, you will have a old set of rigging to refer back to.. You can sit in the seats of the old rigging, see what you like and dislike, how much room YOU need in certain areas and adjust your measurements of the new build accordingly..



This is my cousins 15' Rivermaster with 3/8 poly, rod boxes, 2 live wells, Stainless rigging and a 500 ci direct drive caddy. We took a junk yard engine, didn't bore it just re-ringed, new bearings and the ONLY cam summit sold at the time.. He used to ONLY run the gulf of Mexico and did so for a good 10 years, never needing a gearbox! It worked great for what it was designed to do! It was only until we started running lakes and rivers that he decided to add the gear box and that was not bad either.. Just redid the back engine stand legs and built a new cage..

The only diffrence between a 472 and a 500 is the Piston pin height and the crank everything else is the same. If I was building the motor I would find a 500 crank and get some 500 pistons. The diffrence in torque is worth the expense. You should be able to buy a crank and good pistons for 500-600 dollars. The factory piston are not very strong, don't get me wrong they get the job done but if you are starting from scratch why not build a good lower end.

PS: this is what a high end Caddy motor looks like after 690miles on it. We will do a 100% rebuild, fix any weak links and have her better then ever. That is Allen from S&S in the picture.

Dang Crow, I figured you had about everything on that boat of yours at some point . . . but an odometer ??
Deano

My garmin 198C keeps track of how many miles the boat has gone. It does not take into account the time the motor is running when you are not moving. 95% of that 690miles was put on it from October to January.