The ever-so desireable 308 Heads

gzig5 said

Curious what you think is wearing out faster or preventing rebuild on an aluminum head than on a cast iron one? Valve guides, seals, and seats are wear parts and replaceable on both.

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Let's all ask that question in 30 or 40 years.. We all know the cast can literally be used abused and confused while still being rebuildable. The cast is a lot more forgiving should a valve come loose, or the seats being beat all to snot the aluminum does not fare as well.
While aluminum does provide many performance advantages with weight, modern bowl work, valve sizes ect you can do similar to cast and still keep #s matching. Even at Edelbrock performer RPM level the 308 is a great of the shelf head for around 300 used per pair vs over 1500 per pair.