Just looking back through the service history, my 2.6 has had a head swap sometime in the past. It's not necessarily the same stock head either. There's a ton of Astron motors out there, head numbers M1 through M9, what I need to know is...

- What head numbers were used on the First/Second Gen Magna's (or as much as possible)
- When did the kidney shaped combustion chambers come in (Magna Wiki says TR EFI, AMC says TS only)
- What block number was used in the second gen TR? (W531?)

My engine has "M7" on the head, W531 on the block. W531 sounds about right, basically meaning it has a knock sensor, automatic tensioner, etc... but a Google, wiki and forum search for the M7 head reveals nothing.

Cheers