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Caddy info

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JL242

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I want to use a Cadillac motor for my airboat. Can anyone tell me which one to use?? 500 or 472?? What are the good years, and which one has the most torque?? My next question is what gear reduction ratio would be ideal for a Cadillac power plant. I prefer belt drives, but will take any suggestions. Thanx, JL
 
1970/472, 1969/500....That area. As far as gear reduction, I cant help ya. I run a direct drive 472 on a 13' snake hull, and I pretty much follow the boys everywhere. The Caddy motor idles, and planes out smooth and quietly, I wouldn't wanna ruin it with a box and the extra rpm's that accompany it.
 
I agree w/Flatz Honky. The Cad's put out a lot of torque at low rpm's, which is perfect for running "off the crank". I don't know if I've ever seen one with a gear box.

My favorite (since I had one) is the first year that they built the 500. I'm not sure of the year (69-71), but it had 10:1 compression, which was lowered the next year due to unleaded gas.

Also, if it's a stock motor, be careful because I'm not sure that a stock motor can handle the constantly high rpm's that it will turn with a gear box. The boat builders (Diamondback, Alumitech, Panther, etc.) use motors that are built to handle the rpm's.
 
Got to go with the 500. I to do not run a gear box. I've got a 14' GTO alum. hull and it goes anywhere I need to.
 
I'm looking @ a 15ft Rivermaster hull. Would a Caddy direct Drive, 454 with a gear box, or 0540 supercharged, be the powerplant you would pick??
 
I'm partial to aircraft power on small boats, but on a 15' footer I'd go with the gear reducted 454. The direct drive caddy would be okay too if you never expected to jump up on the hill and run dry. That 454 will take that boat just about anywhere you want to go.
 
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