risers and manifolds
 

I have a1997 Shabah with a 454 mecruiser. I cant find part #s anywhere because when i put in motor serial # it doesnt come up as valid. Any ideas

Re: risers and manifolds
 

Usually part numbers are by the engine generation. They're usually identified by the first two letters in the engine serial number. For example, mine is L0, a Gen VI. Check this site, it might help you narrow down which generation you've got.

Mercruiser Inboard/Outdrive

Scroll down until you see the GM V8 427,502,540 and 572. The 7.4L's are listed there.

Hope this helps.