Can a dry exhaust be routed through the prop exhaust route

[RogersJetboat454]

Re: Can a dry exhaust be routed through the prop exhaust route

Reading about the ill - fated 470 stories...Alum head on a cast block in a Marine aplication....... One - overheat and that motor is done. I would have to pass on this one....

Yeah but...
Kinda an apples-to oranges comparison. While the materials involved are the same, there are a few distinct disadvantages the 470 has over a SBC, that could allow the dissimilar metal parts to become a problem.

-The 470 is an aluminum block with free floating cylinders (no deck surface around the cylinders), while the cylinders of a SBC are surrounded by a full deck of cast iron. Hence more sealing surface for a head gasket, and the block dosen't grow as much.
-The 470 has 4 bolts per cylinder securing the head, where as a SBC has 5 (one of the strong points of the older Chevy engines regardless of their application)
-The 470 has a potential for cooling system issues with it's closed cooling system. If the OP sticks with raw water, or a competent closed cooling system, he shouldn't have issues.

Honestly, regardless of the head installed on an SBC, it's VERY HARD to get an SBC to blow a head gasket. One of the reasons why the engine is so bullet proof.

Now as far as the gains he will realize from the aluminum heads, I'm in agreement with you. The weight savings won't mean much, and most engine builders in the know actually say save the aluminum heads for high compression engines. You can actually make more power with an iron head on a low compression engine, because iron heads don't wick off heat as easily as aluminum, keeping combustion pressures up.

But to each-his-own...

 

[81 Checkmate]

Re: Can a dry exhaust be routed through the prop exhaust route

There ya go - Roger with some technical terms on this subject.......Thats what we need!

So if you can get the alum heads a decent price.....rebuild and go with the GLM alum exhaust manifolds and a alum intake manifold.....then you would have the 200lb + weight savings + some whoomph in the motor.

Or a brand new short block with some extras for the same money!

As said to each-his own.

Good luck!