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502 or 540 build

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boatnutt

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Discussion starter · #1 ·
ok guys need some help deciding what to build. I am going to build a normaly aspirated motor for my 22 eliminator eagle. I like to go fast but i still want to use my silent choice exhaust for pulling tubes or skiers and i know that limits me on the camshaft because of water reversion. I guess i was curios if the change from a 502 to a 540 would be that noticable of a difference. Is it worth the money? Is it more of a gas hog? Does a 540 have the same manarisms of a 502 as far as idling and whatever? Is porting my alluminum rpm heads nessecary? I wouldnt mind 600 to 650 hp. Has anyone got a simalar setup to tell me about fuel consumption. My boat has a 40 gal tank and would it be even possible to drive around the lake (2800 to 3000 rpm) for a couple of hours with this kind of power? :rolleyes: anyways, any input would be very helpful.
 
#2 ·
What engine do you have now?

I'm no expert but if a 540ci is in your budget, I'd go that route! Don't use tall deck heads and the exhaust will bolt right up. You can build a very religable 650hp engine with a 540ci. H ell, build 700hp with it :) .

Then either shelf your current engine or sell it.
 
#3 · (Edited)
You can get reliable 600-625 HP from a NA 502. And another +,-50 HP or more, from a 540. I looked into/researched/asked a million questions about the same options, and went 557 CI.

I'm no expert ...... but if you're going to be pulling tubers and skiers ya gotta consider what you have for an out drive, and how the boat is going to be propped.

If you have a Bravo OD and you were NOT going to pulling skiers, then you would be OK with either a built 502 or a 540, if you stay away from hole shots and are careful overall. But using it as a tow boat, I think you'd have to carry a prop specifically for skiing and tubing, and another prop for general cruising/speed use. If you have the "ski prop" on, and you're not pulling a skier you'd need to be careful about over revving the engine. Or be sure to have a rev limiter. Another consideration is, how will your 22 foot boat handle the hp and speed :eek: :D

Either engine will suck a good amount of fuel. And you will use LOTS of fuel pulling a skier/tuber with either engine. When not towing and with a tall prop, fuel consumption will drop. But either way don't go too far from a marina that sells gas ;)

Cost..... if you already have a BB you plan to use, when you consider the cost of a 540 rotating assembly, intake, good heads for a 540, bigger carb, etc, a built 502 is less $$.

Good luck, and have fun :D

p.s. btw ...... I have a set of new 305 AFRs for sale in the classifieds that would be perfect for a 502 or 509 build. But a little small for a 540, if you're interested ;)
 
Discussion starter · #5 ·
Ya, i need a bigger tank no dought. I have been looking to add a tank under the back seat to the one i have now and switch them with a selinoid switch. Is compression ratio a concideration on fuel comsumption? I was thinking of around 9 to 1 is all.
 
Discussion starter · #6 ·
the reason for low compression is also so i can run the 87 octane fuel from the marina and not have to haul gas in the back of my truck to the lake. I am leaning twords the 540 so i can have good power without working the motor as much. :rolleyes:
 
Discussion starter · #9 ·
The boat had a procharged 502 mag. Never could get the motor to run just right, then found it leaking water in the engine. Got it tuned fine but just seemed to just not run a s good as it should and walla water in the motor. Major bummer!! :angry1: Luckly the boat was set up for speed with 2 ft. hydrolic tabs and hydrolic steering. They should help it to go straight, i hope! :rolleyes:
 
Discussion starter · #11 ·
Temp was way low. I am sure some of the problem i had was condensation, but the intake water jacket apeared to leaking into the lifter valley. I know why procharger does not run a stat only a restrictor, and i dont like it. My last boat had a roots type charger and always had good temp (with a stat) and never had a condensation problem. My new build WILL have a stat to buid some heat.
 
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WETTE VETTE
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