alloy or iron intake manifold for salt water use?

[sarantis]

I 'm going to replace my intake manifold at my gm 350 (old style - carburated, 12 bolts) and i'm wandering a) if there is a difference between the two metals for fresh salt water use and b)can you suggest me a reliable site that sends internationally and to be sure that it will be brand new and not rebuilt?
Thanks in advance

 

[Bondo]

Re: alloy or iron intake manifold for salt water use?

Ayuh,.... How's that barge runnin sarantis,..?? got it sorted out do ya,..??

If you're pumpin' seawater through it, aluminum is probably Not a wise choice...
It's alot less noble than cast iron...
Cast iron will probably be a Best choice between the 2....

I've seen/ heard of bronze lined cast iron intakes, but don't know where you'd find such a thing...

 

[sarantis]

Re: alloy or iron intake manifold for salt water use?

Bond-O and everybody else,hi!
I tried to find a cast iron intake manifold for the model 350 year 87-95 with the center bolts at the 72" in USA in the web but no luck(i don't want any more modifications).So with the half money i ordered in my country an alluminium one( 1" rised ,alittle more Hp) that i'll have it in my hands tommorow, i Know it's not a wise choise but i had no other way to gain some chances for my boat to work properly (for third summer overheating problems).Do you know what is the intake bolt torquing for an alluminium intake manifold? For cast iron the manual says 30 Lbs.ft .For the alluminium i suppose a little lower?
Thanks in advance

 

[Bondo]

Re: alloy or iron intake manifold for salt water use?

Do you know what is the intake bolt torquing for an alluminium intake manifold? For cast iron the manual says 30 Lbs.ft .For the alluminium i suppose a little lower?

Ayuh,.... I'd go with the Same torque values,...

I'd also toss the valley gasket rubber pieces if they come in your set,...
Just run a bead of silicone across each end of the valley,.. Let it set up abit,...
Then drop on, 'n torque down the manifold...

I hope the aluminum works out for ya,....

 

[wca_tim]

Re: alloy or iron intake manifold for salt water use?

um... in brackish or salt, the manifold will serve as an anode for the entire engine and might not be long before it is pretty much dissolved...

I run aluminum manifolds - both exhaust and intake, and now heads, and sometimes run in brackish. I see very little corrosion of the water passages on the intake(s) using screw in zinc pencil anodes... I just swapped an intake off that had been on there for almost 2 years.