alum head vs iron head
 

besides the weight savings of alum heads what other advantages are there....and is it worth the extra $

You can generally run more compression, they disappate heat better. I used Dart 180cc Pro1 heads on my 388 along with its EFI aluminum intake I shaved a tone of weight off the engine, almost 100 lbs from what I remember.

these two reasons are enough to justify the additional cost!

resale will be better as well when it's time to sell.

the alumium heads do not like salt water.cast iron holds up better in salt water.what type of cooling,closed water or fresh water?

The boat actually sits a little higher at rest in the rear now, the previous water line is a good confirmation lol

Agreed- No salt water here :)

you can get them hard anodized for the salt water...just bought 2 sets of AFR alum. heads and had them hard anodized them...I got them for use with new whipples, better flow, weight, better heat disapate...

Dart can do this too..........

Good point.

Yes they can, checked with Dart heads before going with AFRs...

So which manufacturer are you going with? afr, dart, merlin..

We sell both, depends on budget when you get down to it. I would say Dart and AFR are the best or at the top of the list.

I went with AFR, every head to head test I saw, AFR made more peak and average power over everyone else. They flow more with smaller volume runners, which means more low end torque and better idle.

Correct!

Heres a question. Say you have a 8:1 aluminum headed blower engine, intercooler. And then you have a 9:1 Iron headed blower engine, but with a intercooler.

Assuming the quench, head design, cam, and all other parameters are identical. Which engine can run more boost without detonating?? The lower compression non intercooled version, or iron headed intercooled one with more compression??

The aluminum head will always be better, intercooled or not. They just dissapate heat better and faster. Iron heads can also have "hot spots" that can lead to detonation.

Also if you ever hurt an aluminum head, most of the time it can be repaired where a steel head cannot.

What comp ratio are you guys with alum going with?.......the only other concern was pairing an alum head to an iron block but I guess it been done enough times that any/most engine builders can do this?

What is the gerneral cost of hard anodizing?

when i got my AFR heads 3 weeks ago it was about a $150 option, per set, when i priced Brodix heads they were almost $500 or more a set, to hard anodize....

Look at all the production car engines that have been doing this for decades.

All you need is the correct head gasket.

I would also suggest port matching the heads and intake together. I paid around $250 the last time I had this done by Dean Gellner (sp)

I'm running 9:1 on my 388 SBC. 87 octane, Dart Pro1 180 cc heads, TPIS ZZ9 camshaft, TorkLink Intake, TPIS 90mm TB, 24 lb injectors, 425 HP @ 5400 RPM 441 ft. lbs @ 4700 RPM. This is in full marine dress through the exhaust manifolds and 3 inch "transom exhaust" out the back of the dyno cell.

Aluminum heads on an iron block is a concern from 40 years ago :) Many (almost all) engines made today have aluminum heads. More manufacturers are using aluminum blocks now but aluminum heads with iron blocks have been used with excellent success and no worries.

Stay away from pro comp heads for marine use.

if you do a little research on the differences between the 2 metals allu. vs iron/steel you will come to the conclusion that aluminum is a far superior material in just about all aspects
the biggest disadvantage to aluminum is that in a motor application if any overheating occurs even in small pockets this can adversely affect the metal itself
warping of heads is probably the most common problem
i wonder if some of the real serious hp enthusiasts are using billet aluminum blocks in marine application like the racing boys

How about for any use??? lol Chinese quality and a Chinese price.

Pro Comp is from Australia

You are correct......... I retract my statement. I had Professional Products on the brain.

Don't retract your statement! Procomp heads ARE made in China! They are routed through Austraila not MADE there! Do a quick google search on this and you'll find lots of info on them 90% of it bad! Do yourself a favor and stick with Dart, AFR, Merlin or Brodix.

Either way that's cheap insurance IMO.
Thanks

That's what I thought but wasn't 100% sure, so now you confirmed what my wife tells me is false................ I DO know everything and I'm never wrong!
I've seen several alum. SBC heads that look identical but have different name and the same poor quality. Patriot, Pro Comp, Professional Products etc.... People buy them because they are cheap and don't care to investigate why whether it's poor design, poor flow characteristics, poor chamber design etc.... We only use American made parts on our engines and it's all we sell. Says so right on the top of our homepage :)


hahaha

So what type of heads are on the 496,502,525,575 alum or iron/steel

Merc. 496 heads are iron unless you have installed a set of our all USA made BigPower 100 lbs. less per pair aluminum heads!

Could not resist patting myself on the back, HA!

Best Regards,
Ray @ Raylar

Good one ray!.

If using alum heads is so much more efficient then iron heads you would think it would be a merc standard then?
It couldn't be that much more $$ ?

100 less pounds is like leaving one of your kids back at the dock :)

that is one thing i dont understand....with their expertise and knowledge,why didnt gm or merc build a better,more efficient head for that motor?almost seems like they build those ''chitty'' heads on purpose....whats the point?

Leaving the bitc# home. That's 100lb that really slows a boat up big time. And cheaper than a set of aluminum heads

Probably because iron heads are cheaper, hold up better in salt, and probably stand up to overheating better. Merc did use aluminum heads on the 900sc, and I think the 525efi

and thats exactly the point if most guys on here swear by alum heads and yet merc,volvo use the iron ones, theres gottta be a reason. what do the the other major engine builders use (teague,sterling ,chief etc) it really cant be the $ savings..could it be lower maintenance

You can also port heads like the Dart 308 Iron Eagles to flow as well as heads like the AFR 320 CNC. About any head can be made will work with blowers, but the trick is making power with a flat torque curve in a NA application. Who can make cast iron and aluminum heads work in marine? Jim Valako....
Save your time and $, it took me 10 years and numerous mistakes to figure out how good Jim is in making power.

I siezed an engine from a blown impeller at 3/4 throttle and had to paddle back to shore. Took about an hour to replace the impeller, check the oil, and I was back in business. Try that with aluminum heads :)

My comments and plug are for our aluminum cylinder heads that only used on the 496 closed cooling equipped marine and vehicle engines. Iron heads are preffered on a raw water cooled marine engine that is used in salt water, If an aluminum head is used in a raw fresh water and serviced properly it will hold up just fine. As for overheating an engine, iron heads can crack as easily as aluminum heads can warp and crack from serious overheating. As for the 100lb. weight savings , I would never tell a boater to buy aluminum heads just to save a 100lbs. I can tell you as an expierenced engine builder I can always make more power from an aluinum cylinder head than I can from an iron head, why, because I can put more compression in the cylinder without the detonation from the added cylinder temperatures seen with an iron head at the same compression ratio. Show me a 2002 or newer design engine with iron heads! Seen a few racing engines in the last 20 years and I have seen almost none using iron heads by choice!
Iron BBc heads have been in the marine engine trade for years and will be here for a few more, but not much longer than that.

Best Regards,
Ray @ Raylar

I agree with everything below..... Aluminum heads can be repaired, you can run more compression which increases cylinder pressure and makes more power, they are lighter, they don't crack as easily as iron, dissapate heat better which is even more important when running low octane fuel 9less detonation prone).