mercruiser 525 headers
 

i should know this but i dont,will the factory cmi 525 headers bolt up to standard bbc heads??

Yep

no. but they can be modified .need to drill 4 holes on each header .the 525 s have a 3/8 ths offset bolt on each cyl . nice that merc did that so you could only use their headers

Oops . . . . Are the 500 and 525 different headers?

yes they are .525 600 and 700 .i think once the patent ran out cmi will make them w both patterns .i think they do now

Bolt pattern is different on the 525 heads but they can probably be redrilled as mentioned. There is not much room for the end hole though.

thanks for the help. when the headers show up this week ill fire the drill up and reposition the holes according to my exhaust gaskets,wes

easy to do just copy the gasket . but the stainless flange is tough to drill

so does hold true for set of 99 etop 500 efi headers too, just bought a set of AfR heads, didn't bother to check to see if the header bolt up...

no only . only 525s 600 700