Can someone straighten out my head!!!
Port side ID# OL414792
Star side ID# OL414804
I find both sets of serial numbers on 500 generation plus and 500 bulldogs which I think are 540's. They have B&M huffers and 650 double pumpers topside.
Can you tell the difference between 500's and 540's just by looking.

the reg. 500's are short deck and the 500 bulldogs are talldeck blocks ( yes 540's ).
the way u can tell is by looking at the distance between the waterpump (crosover) uper bolt holes to the head bottom..on a shortdeck they are with in 1/8 of an inch and on the talldeck they are 3/8 inch + away from the head bottom.

PM me your no. and ill get you in touch with the biulder, he,s a freind of mine ,I do know they are 502, one side is punched out to 509

I know these engines, I assembled them. The Starboard side had dropped a valve so it needed a .030 bore to clean up the cyls. We installed JE forged pistons at 8.9 comp. All new stainless Manley valves, everything magged and rods reconeditioned. The port engine had just been rebuilt, all I did was check all the clearances, reconditioned the rods and put new rings and bearings in it. They are 502`s, (starbord is now 509), what it says on the valve covers (apba or something) is who built them for Mercury racing. They are supposed to make 600 hp.

The port blower is a rebuilt one also. Please check the oil in them once in a while! (pipe plug on front, 20-50 oil is fine)

I hope I was some help, you have a good boat..... Ive driven it several times and to be honest the only reason you have it and not me is when it was time to sell I was too worried about the economy to bite the nut!

Have fun with it! Chuck.

All the 500 Bulldogs are 540ci tall decks and make 500hp.

If you can't tell if they are tall decks, then have a merc dealer run the serial numbers.

Oh, they are short deck gen 5 blocks.

Is your head straightened out yet