Merc 470 ext manifolds

[Eric H]

Can anyone explain why there are 2 types of lower manifolds? There is an aluminum version and an almost identical cast version. <br /><br />I ask because it is time to spend money and I can spend it either way. I see no reason why they will not interchange as long as you use the correct riser.<br /><br />My thought's are the aluminum style provides a respectable weight savings. I also see the cast version as being more robust in the long term.<br /><br />Can someone who knows these motors please comment? Merc had to have something in mind when they changed the style.

 

[Bob_VT]

Re: Merc 470 ext manifolds

I changed mine last year to the aluminum. I was able to find them easier than the cast iron ones when I shopped for them. It really should not make any differance except weight. I had to change both to get them to match and they seemed better than the cast. They might be less prone to cracking.<br /><br />The 470 is an aluminum block with a cat iron head.<br /><br />Bob