500hp/good or bad

They are total junk. I will swap you straight across for my stock 502 black engine. Because I`m a nice guy like that.


Seriously - They are great, but the valve springs have been an issue with the carb engines. They usually need to be replaced at 200 hours.

Like Donman said, make sure the springs have been done every 200 hours. Solid engines !

Just went through a set for a customer,,,,, high hours and tired,,, still ran like champs.

Dont cheap out for the 200 hour service and try and have the springs changed on the motor.

I will get arguments on this,,,, but over 50% of the 500 hp, and 500 efi 250 hour services I have done have had head gaskets blown and guide issues, so spent the extra cash and do it right.

These are great engines.

I had a leaking lifter when I did my springs. Ended up changing all the lifter too.

Canada Jeff said:

Like Donman said, make sure the springs have been done every 200 hours. Solid engines !

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Correct me if I am wrong but I don't think that the springs have to be changed every 200 hrs but just the first 200 hrs and upgrade to some better springs???

Run_em_Hard said:

Correct me if I am wrong but I don't think that the springs have to be changed every 200 hrs but just the first 200 hrs and upgrade to some better springs???

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Yes, that was the buzz. The springs should be changed out around 250hrs or before. Almost like a recall; the inner springs were prone to breakage from what I was told.

Run_em_Hard said:

Correct me if I am wrong but I don't think that the springs have to be changed every 200 hrs but just the first 200 hrs and upgrade to some better springs???

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Yes, I should have been more specific. You are correct.

what size of carb came with the 500

Not able to do them w/o pulling the heads? What happens there? Just curious...

rumble man said:

what size of carb came with the 500

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Holley 800 cfm double-pump

RSCHAP1 said:

Not able to do them w/o pulling the heads? What happens there? Just curious...

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You should be able to change them w/o pulling the heads, just have to pressurize the cylinder.

Mine were done with the heads on.

Does the 500 mean 500hp on the prop or just 500hp on the motor crank?

470 @ prop

Great motors we have had quite a few boats with them. The 45 is the first with the EFI's. Other than springs no real problems

And a whole lot easier to work on don't need a computer to fix.

Run_em_Hard said:

You should be able to change them w/o pulling the heads, just have to pressurize the cylinder.

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you can,,,, but like I stated above,,,, many have head gasket issues, guide issues,,,,, and now with this oxygenated fuel,,, good time to take a look at valve seats