ProMaxx and IMM aluminum small block LA heads

Good afternoon,

I am doing some research for my upcoming 340 build and have come across the heads in the links below. I can't find much on the internet about either of these and wanted to know if any of you have purchased and ran them on your engines. I've read some great things about IMM in numerous engine build articles, but I haven't seen any builds with their aluminum heads. My 340 is a 1972, and has the original J heads on it that will require a complete rebuild to be used. Rather than spending the money on them, I'm willing to ante up a little more $ for a modern, aluminum head. Any feedback would be appreciated.

Maxx 171 SB Mopar (Sold in Pairs) - PROMAXX Performance Products

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