Cam specs
 

does anyone "know" what the cam specs are for the stock 502 mag efi 1999 and up, that would be merc # 431-850478

Lift .485 intake .485 exhaust
Duration 224 intake 224 exhaust

115.5 centerline.....

I have a 1996 502EFI and according to www.mercuiserparts.com it calls for the same cam part # 431-850478. My Mercury manual shows that my 502 hydraulic roller cam has [email protected] for lift and 227 on exhaust and 211 on intake for duration. I have not checked duration numbers but I have verified the .581 lift and it is correct. Now you guys got me wondering??? :rolleyes:

I'm showing 502GenVI rectangle port 8.75:1 compression is 224-224 duration, .483"-.483" lift and 115.5 LSA. ChevyCam part # 12551622 merc.# 431-850478:cool:

FloridianSon> Is that the cam number for a 1999 502mag mpi and if so do you show the same cam for 1996 502mag mpi. Do you know what cam # is called for on 96 motor. Just wonder about on line parts look up.

The only ones I show are GM# 3904359-merc#431-4734 in the 454-oval port. The GM#14096209 Merc#431-9830 in the 454-502 w/ rect. ports flat lifter.TheGM#10185060 same as 14096209 but 5* advanced flat lifter.The GM 12552296 merc #431-850478 in the 454 oval port roller lifter Gen VI.The GM 12551622 merc#431-850478 in the 454-502 w/rect ports roller Gen VI.The crane#169611 merc#2409-848491 in the 500hp w/ rect. ports speacal adj. valvetrain roller lifter Gen V-VI.The GM# 24502611 in the 454-502 HO crate w/ rect ports roller GenVI this is a high performance replacement.And the GM #12366543 in the 502/500 hp crate w/ oval ports adj. valvetrain roller Gen VI.This to is GM high performance replacement cam shaft and the one I am going to be running in my 502 with the Merlins!:cool: