500 caddy tweeking tips?

[divecaptchris1]

Running a 500 caddy on a 15' panther hull with polly, 72 l x l 44 stick prop. only getting 2500 rpms WOT, running the q-jet carb, motor runs like a top, no missing or hesitation, but ifeel I should be getting 3-500 more outa her. Anyone got any tips for getting the last few hundred outa her without a rebuild or other Large $$ undertakings

[John Fenner]

http://www.southernairboat.com/phpBB3/v ... y+upgrades
Plenty to read in the search forum under 500 Caddy.

[John Fenner]

There are many simple tricks as well to gain power on low bucks.

[:)]

A good dd caddy Cam to start and get a prop that it will turn 2900 or so.

[Deano]

What have you already done to it, or is it 100% stock?

Is that the prop CowboyRock had ? If so, I thought it was a paddle.

[divecaptchris1]

What have you already done to it, or is it 100% stock?

Is that the prop CowboyRock had ? If so, I thought it was a paddle.

deano, it is stock as far as I know, yes it is the prop from cowboy, however all that have looked at it say it is a stick. as you well know I don't have a clue . I think timing is issue from reading posts on here. But really haven't learned enough to know where to set it! Im a welder and not much of a mechanic! The Motor sat for a long time, and has seamed to run better each time out, of course that is two times out for about 1 hour each

[Deano]

Glad to hear that it's really a stick. That will work. A 44" paddle would be a problem to spin much more.

You really need to put a timing chain in it right on the front side if that hasn't been done.
The one you want is Cloyes #9-1139, iirc. This is not something to put off now that you are running it.
A hundred bucks now, or a rebuild later (maybe sooner than later).

When you do that, confirm that your timing marks for TDC are correct on the balancer and marker. Motors this old could have been Frankensteined along the way and there were 4 or 5 different ones used over the years. You can put a spring kit in the distributor or lock the timing. As far as your timing goes 32 degrees total is good to start, after you have done the above.

If you can spend the $300 for a DD#1 cam and lifters from MTS, that is likely your single biggest bang for the buck.
A 1" spacer between the factory intake and the carburator will help as well.

Do a search, and read away, there's probably more here than you even want to read.
I believe you have my number, feel free to call if you have any questions.

[Cowboy Rock]

Chris,,, I thought it was a Paddle,,, I was told if the blade was wider than the hub it was a Paddle,,, Either way I hope it is what you need for your boat,,, Good luck,,,

[Thunder200]

PM SideJobs on here. He has got one bad to the bone Direct Drive Caddy for sure. He may have some Ideas for you?

[One Eyed Gator]

Like Deano said Timing chain it a must. Cloyes.

Cam and lifters for DD MTS DD1 or better yet DD2 cam have to cut down valve guides.

Good Valve seal is important. So good 3 angle valve and with a spring kit for DD2 cam. I put a reworked set on my motor made a noticeable difference.

There several different Pulley's 1 is stamped pully with harmonic balancer( light) 1 is a cast pully that is balanced, has no balancer Very heavy. Water pump pulleys are the same way there is a stamped steel and cast. Any rotation weight is good the get rid of.

I put the Aluminum set from MTS with there alternator bracket setup. Alternate is for the small body alt I believe SI10.

Running a wood prop a longer prop adapter 3-6" to get prop away from motor.

Good HEI Dist and Coil. There was one year the stock HEI would only add 8 degree of advance I think it was 74'.

Weld exhaust crossout shut on intake manifold.

Definite verify top dead center and pulley mark many different combonations. Also polish oil pump bypass plunge they tend to stick, may even want to shim spring. Get the good copper exhust gaskets from MTS, the other crap does not last.

Just a few quick thoughts.

[boobidges]

Is thatgood advice for a 472 also?

[boobidges]

Is thatgood advice for a 472 also?

[sidejobs]

All great advice ...however nothing you do will benefit you as much as switching from a wood to a composite prop. I promise no one will argue that on a dd !

[caddy]

All great advice ...however nothing you do will benefit you as much as switching from a wood to a composite prop. I promise no one will argue that on a dd !

X2

[One Eyed Gator]

oops

[One Eyed Gator]

From what I have learned from the few dedicated Caddy guys on here, dd power is in the little detail. You not making huge hp so all the little details add up. Also the set-up of the hull and rigging make a big difference as well. I can drive my boat thru and over some crazy stuff, put someone in the seat the is used to all kinds of power they cant make it move, oops sometime I cant either Darn DD.

I would also agree that the Carbon prop is the single best change you can make. My motor doesn't run like some but it has been run hard from over 10 ten years. Finally having to replace the crank. Hope to be back on the water so. With the heat I been hearing Juniper and silver glenn call my name.

Faster than some slower than most but sliding and catching fish.

Setup is alumitec, 3/8 poly with 72 472 and a 72" 3 bld H (hurts my ears just saying it, but one on the better all round props. Really want to try 3 bld NGH.

[John Fenner]

Look for the tip on using a spacer plate along with filling the void in the plenum that gains about 2/400 rpm.

[One Eyed Gator]

John is right, Crowhater has always talked about the 1" carb spacer that is divided down the middle yielding a few hundred RPM gain.

[Deano]

While I think the specifics of the divider could likely be debated, it is pretty well universally agreed that the factory intake lacks sufficient volume due to it's design (to fit under the hood). Adding a spacer helps rectify this lacking volume. On that note, as John eluded to, there is some to be gained by blocking the exhaust bypass. This was done to aid in fast warm up under a hood with a ducted intake, but is not worth the trade off of having a perpetually heated intake charge in our application. Cooler air is denser, and will yeild better results. It seems as though Edelbrock would have thought of this.

[One Eyed Gator]

I did have the exhaust passages welded up on my Edelbrock intake. But I cannot compare as I never had the intake on before the passages were welded. I did not have plenum divider weld-up. I have also run 5 different carb set-ups 500 2 brl, 750 edelbrock, 650 holley vaccum, 750 summit and a 850 holley dp. Each ran 1/2 ass until I spent a great deal of time tuning it. Once tuned with AF ratio meter they were about the same. Edelbrock like to lean out on top though, try a few things and could never get it right. also the Summit 750 have a lean surge just before the secondaries kicked in, chased that for a while finally went back to the 2 brl, best alround.

[John Fenner]

Try a 450 Holley with the rear metering block kit, use 68 jets in the primaries, and 73 jets in the secondaries, it will have alot of snap to it plus the cruise will save fuel.

[crowhater]

I ran the same set up for years! I had the same hull, same engine and it was 100% stock except for a cloytes timing chain. The prop I used was a 72x44 Florida airboats paddle prop and I turned it to 3000-3100 rpm. It took a bunch of tweaking to get to that point but I did it and I did not have to spend a bunch of money on go fast parts. The power is there it is just a matter of getting the combo dialed in. My boat could stop and go on wet sand with just me in it and could run standard dry ground loaded. I built the engine myself in the garage with a standard Cadillac master rebuild kit. The engine was .30 over and had 10.1 compression. The intake was factory and the carb was a factory quad. The headers were those cheap chrome block hugger short tubes off eBay and they cost like $200.00. I wish I still had the boat, it was one of the best airboats I ever owned. It would make 8mpg, never broke down, and run 50+mph easy.

[divecaptchris1]

Chris,,, I thought it was a Paddle,,, I was told if the blade was wider than the hub it was a Paddle,,, Either way I hope it is what you need for your boat,,, Good luck,,,

No issue with the prop! I was hoping it was a stick! my issues are with the motor now! lol!