Hey Guys how can you tell if your 500's are Bulldogs or not by the serial number........ thanks

Bulldogs and 500's are two entirely different engines. The Bulldogs are 540 CID while the 500's are only 500 CID. The serial numbers should tell you what you have.

how many HP are the bulldogs ?

Merc rated them at 500 HP, same as the 500's. They were a stronger running engine though.

So who do I call at mercury to find out? Any phone numbers?
thanks

serial number plus your local merc dealer

My Bulldog intake Manifolds have a 'TD" Cast after the brand Name..(tall Deck}

The intake manifolds on the Bulldogs are black, the HP500's
are blue.

The flame arrestors on the Bulldogs say Bulldog

Bulldogs have a carb spacer under the carb,
HP500's dont.

Thanks Guys

Get bulldogs if you can find them. They make the same power as the 500HP's, but will make a lot more power with a cam and heads.