Aluminium vs cast what is better?

[belliswood]

Need to replace manifolds and risers and I see that Michigan motors have aluminium manifolds for my motors. Is there any advantage to putting aluminimum on instead of the cast. Pro's Con's, what do you think....

 

[moparlvr4406]

advantages as I see it would be weight and heat disipation rates
disadvantage would be corrosion if you are in salt and potential warpage issues

 

[fwebster]

You might want to read the first post on this thread:

http://clubsearay.com/showthread.php/6038-Heads-Up-early-Mercruiser-8-1-s-w-aluminum-manifolds

If you have sea water cooled engines, or even freshwater cooled ones with sea water exhausting thru the manifolds, then aluminum will not work, as Mercruiser found out.

 

[belliswood]

Thanks, aluminimum is definatly out.....

 

[kevin27]

I perferr OEM.

 

[rcknecht]

I have your motors and have HiTek SS one piece exhausts. They weigh 200+ lbs lighter than the Cast, and they are one piece. the water exhausts far from the engine, so ther is very little chance for water instrusion. They each ave a 1/2 inch zinc for dissimilar metal bonding. They provide more HP because they are headers and the exhaust flow is less restricted... If you want a change, I would go with SS before AL...