PRHeads
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I’ve actually never had my hands on original 518’s.
But, I think I’d refer the M’s if you can find a set that doesn’t have a big core shift problem, or the chambers are way too small for your combo.
As I recall, there’s a noticeable difference in the chamber volume spec depending on the year?
But, fundamentally, stock 518’s that haven’t been cobbled up to the point where they’re not legal anymore…….should be fine.
I’m not sure if you know this or not, but the M’s were also available from MP with the seats cut for 2.14/1.81 valve sizes, so you’d want to make sure you didn’t get those.
But, I think I’d refer the M’s if you can find a set that doesn’t have a big core shift problem, or the chambers are way too small for your combo.
As I recall, there’s a noticeable difference in the chamber volume spec depending on the year?
But, fundamentally, stock 518’s that haven’t been cobbled up to the point where they’re not legal anymore…….should be fine.
I’m not sure if you know this or not, but the M’s were also available from MP with the seats cut for 2.14/1.81 valve sizes, so you’d want to make sure you didn’t get those.
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