Aluminum castings can be anodized after all machining operations have been performed. Used heads can be anodized, but must be stripped and cleaned first.

Properly done, anodizing completely prevents subsequent corrosion, but it the anodizing is scratched thru - it opens a "wound" that can infect the surrounding areas.

Many anodized castings are improperly "gasket matched" or deburred by engine builders as a result of "habit" and this gives entry to a path of corrosion. Once anodized, the coated surface must be preserved.

As a side note, anodizing is a form of corrosion. The electrical current ATTACKS the aluminum and changes the upper surface into a form of mineral (aluminum oxide). Once changed, this surface will NOT conduct current or react to the normal range of antagonists that would normally continue to attack aluminum.

MC

Would you buy BBC iron heads if the pricing, HP/TQ results and acceleration were the same as as CNC aluminum? Say 800+ HP N/A? Jim Valako has made us 3 sets. The relativety small increase in boat weight won't likely show on the GPS and they should last indefinitely.
Ben

Ok ..you got my attention .....how to you inject the Vinegar? Hose end sprayer? ....If you look at the salt away type injector the hole the water has to flow thru is ridiculous ....I would sat 1/4" or smaller ...m

Who does this for heads?

From experience - find a 351 and do some work to that engine. That 302 will need a lot of exotic parts to make it produce a noticeable HP increase.
I went from a merc. 188 ( 302) at 188 HP stock to over 500 HP with more money spent than you can imagine.
I had a SMALL engine bay and the engine cover was hitting the exhaust. Glastron Carlson CVX 18.
I wish I could have gone to a 351.
everything should bolt up the same. the engine will be a little bit taller and wider.
Your exhaust will move but if you are running rubber hose connectors they should give that much.

closed coolant system .

just changed my motors to closed coolant system.

This thread was started ages ago by the guy with the 302.

Besides that, I vote for closed cooling too, however, there was a guy on here recently that had his heads rotted from outside. Salt air/water attacked areas near exhaust ports/header flanges.

If you gets heads hard anodized, make sure they are done after machining, not before. As mentioned, any areas with anodizing that have been machined off, well, defeats all purposes of anodizing. Canfield used to anodize after. I'm not sure about Dart and Brodix - must ask ! I know AFR machines after anodizing. :(

If getting heads and/or intake hard anodized after machining, make sure they keep atleast threaded head accessory holes (for ground cables) and spark plug holes non anodized. You need plugs grounded ! I grounded coolant temp sensors on their exterior, since the t-stat housing will be electrically dead, or unless you ground the housings with a separate ground wire. T-stat housing normally grounds thru intake which grounds thru...... :)

absolute plating in Norwood,Ma.located on Bridge st.
they did our 1075 merc heads to a mil spec coating and then some.these were brand new heads,they have to be,also had to remove guides and all the helicoils.
hope this helps a little.