Long-off 340 build

Martin said

I mentioned the Hughes because they have the lowered oil band. COMP Cams might have that also, just verify. Again all of this depends on your lifter bores...if they are chamfered and you don't have the correct lifters, you will have oil pressure issues. The Hughes link that I posted earlier discuss this problem in more detail.

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Well I was all for the Hughes lifters, til I saw this on their page:
"Lifters will drop in with heads on. (Stock iron only). Will not drop in with aluminum heads."

What is the weight difference between the stock heads and an aluminum set? How good is the cooling on stock? If the weight difference is nominal, and cooling is still decent, then I may consider foregoing the aluminum heads.