[VCho455]

I didn't find any threads concerning this in my searches. So let's hear your story.

With your mileage please spec out which aluminum heads your running, your compression ratio, camshaft, rocker ratios and spring pressure.

Those things might make any comparisons more valuable.

Any information on how you use the vehicle would be nice too. Daily driver or Cannonball run competitor.

Anyone out there with 50 or 75 thousand miles on a set?

What problems if any has anyone encountered with mileage above say 30k?

I know folks around here don't like to brag, so don't be shy, post up!

[Steve C.]

Calling HWYSTR455 to report in

"The one solid roller I had I rebuilt the heads at @120k miles, and that engine went over 200k street miles with the same cam"


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[PunchT37]

These have been around since 2010. HR cam. 246/253, 600 lift with 1.5 rockers, 330 cfm, 10.3 compress. Forget spring pressures. Quiet with 10w-30 or 20w-50. Drive anywhere if you feel like feeding this thing. T400 with 3.55 gears. No problems. No leaks, runs 175 degrees even on hot days.

[PAUL K]

Not sure what you are getting at, or if your just curious. I don't see why there would be long term issues with aluminum heads but if you find any, they maybe on the early design RPM heads using a poor choice of head gasket.

[indymanjoe]

i like this post because some people drive to car shows and some drive to the drag strip, hot lap many times then go for a 300 mile cruise. I love my dependable iron heads. curious what the real world results of aluminum is also.

[Formulajones]

Same as iron. I've run both for decades and no discernable difference as far as mileage and durability goes. OEM's have used aluminum heads for decades on production vehicles that go 100's of thousands of miles.

[steve25]

In general It’s not at all about how many miles you have driven it’s all about how many heat up and cool down sessions the motor has gone through.

In terms of pure race motors it’s about how hp equals heat and the gradual loss of the original tempering done to the heads and then stuff moves around and at times the head bolts will sink down into the casting and valve seats can come loose, and then your in for expensive distructive things befalling you!

[Formulajones]

I've never had any of those issues Steve, but then again I don't buy the cheap chinese heads either, which have already had well documented issues of seat problems among other things.

I've had a set of AFR's on my BBC for 25 years and haven't touched them since installed. That engine makes peak power at 6300 and I shift it at 6500. Drive it everywhere, 300-400 mile road trips, thousands of miles, most of the time hard street miles, and love drag racing the car when I can. Haven't had a valve cover off of it. No weird valve guide wear issues, no seats falling out, no ticking noises.

Not our only engine with aluminum heads either. I just don't experience any issues that people are hinting at with aluminum heads on a street/strip engine. In fact building another engine right now for a daily driver. Another set of AFR's to be exact. Not even the least bit worried about longevity and durability. Good quality machine work, precise assembly with good quality (not cheap) parts and that engine will go 100k miles with regular maintenance and I don't even think twice about it.

For what it's worth, I get about the same mileage/wear from iron heads. Typically 70,000-100,000 miles and they are in need of guide replacement and seat work. No head is immune to that. Even many OEM engines from the 60's-70's-80's were that way and would became oil suckers when approaching the 6 figure mileage mark. OEM's now go even further, and using aluminum heads to boot, for decades now. :shrug:

[Half-Inch Stud]

Galvanic story; so electroplating a sacrificial aluminum to iron is easy if a more positive voltage is on the Aluminum.

Like well a Starter grounded to iron, with the Batt NEG cable to the Block is okay, but the Alternator case going thru Al-to-iron to reach the Batt NEG cable ought cause bubbles while driving at night. Assuming the coolant has some ionic content. Dirty coolant sure does.

Wonder if Barr's stop leak provides ionic content.

Anyways tiny purple bubbles, go laughing thru you casting, and they want to take casting metal with you to the iron in the sump.

Any tear down would have posted a localized electroplating pitting by now, if it were a systemic concern. Yea.

[steve25]

Yes, I agree with you in general , but in terms of a iron head going south back in the 50s thru to the 80s mineral based oils where still overwhelming used by owners .
I have no doubt that a new product head on a motor was made of iron and ran a synthetic oil that the usefull life span would be a tad better then a Aluminum head given the same guide and seat material.

[Formulajones]

I agree that oils have gotten better and helps with longevity, but I don't agree that an iron head has a longer seat and guide life span than aluminum. I just haven't seen it.

Way too many OEM engines out there with aluminum heads that say otherwise.

Even when refreshing heads these days, using the same materials, whether an iron or aluminum head, they have the same chance of longevity that I've had experience with. No discernable difference. If there is an issue, premature wear or what ever it is, it's usually the fault of poor machine work, setting guides up too tight and galling, or poor assembly with horrible rocker arm geometry that accelerates wear.

There are quite a few new aluminum heads on the market that are reported to have guides too tight. Some head builders report Edelbrock is one that tends to do that. It's a big reason why every set of aluminum heads I buy brand new out of the box go straight to the machine shop to check guide clearance and valve job for sealing properly, correct springs etc..... I never just toss them on the engine, that's asking for trouble.

[i82much]

I find they respond very poorly compared to iron heads when I use my impact wrench to install the header bolts.

[Formulajones]

.....

[VCho455]

Just being curious about the Pontiac aftermarket heads. I have a set of early E-heads with about 12k on them. They are on a de-stroked 455 that makes 450hp/485tq on the chassis dyno. In addition I have a set of KRE's at the machine shop along with the rest of the engine. It should be ready for assembly over the winter.

I do have experience with OE aluminum heads (and blocks). My Alfa Romeo has 170K on it and it is now needing some serious head work. Not to mention the 30 or 40 motorcycles I've owned over the years. (I was motorcycle mechanic in the 1970s.)

One expects OE stuff to go the distance but, there's no recalls or other official feedback on the aftermarket. (Unfortunately)

I have no axe to grind. I just was curious after a conversation with some people a couple weeks ago. After searching around I didn't see any posted discussions on the topic so I posed the question.

[VCho455]

Originally Posted by Formulajones

.....

X TWO!!

[Formulajones]

Originally Posted by VCho455

Just being curious about the Pontiac aftermarket heads. I have a set of early E-heads with about 12k on them. They are on a de-stroked 455 that makes 450hp/485tq on the chassis dyno. In addition I have a set of KRE's at the machine shop along with the rest of the engine. It should be ready for assembly over the winter.

I do have experience with OE aluminum heads (and blocks). My Alfa Romeo has 170K on it and it is now needing some serious head work. Not to mention the 30 or 40 motorcycles I've owned over the years. (I was motorcycle mechanic in the 1970s.)

One expects OE stuff to go the distance but, there's no recalls or other official feedback on the aftermarket. (Unfortunately)

I have no axe to grind. I just was curious after a conversation with some people a couple weeks ago. After searching around I didn't see any posted discussions on the topic so I posed the question.

Speaking of OEM aluminum and aftermarket aluminum, I believe if same materials are used during the reman process I wouldn't expect any difference between them as far as longevity, as long as the machine processes are done correctly.
I think a lot of these variables can be attributed to different machine shops using different practices.

I'm not at all familiar with alfa romeo, I don't do the foreign stuff here and have no experience with how they do things at all. I know motorcycles are a different ball game though with a ton of variables.