Hi Mike Welcome - the wooden block under the seat rail is standard. I'm 6'3" (190cm) and have plenty of headroom in my TD21. You must be tall! Have the seats been refurbished, because if the stuffing is too stiff, that might contribute? You should sink into them a little, like a comfortable armchair. There are 2 "factory" manuals for the TE21. An owner's "Manual of Instructions" (which has very basic maintenance guidance) and a Catalogue of Spare Parts, which has useful diagrams of the important technical parts of the car. Both of these appear frequently on eBay, or you can download digital copies - if you would like me to send you them, let me know. I'm not sure either will help with your specific issue - I'd suggest showing it to an Alvis expert, depending on where you live (plenty around the UK Midlands) There is no workshop manual. As well as the Culshaw book wheich Richard recommends (essential!), there is a "50th Anniversary Collection" of technical articles on 3-litres which the AOC is planning to re-print soon, so look out for that. Otherwise, you could post the question on the AOC/Avis Cars Facebook pages and see what answers you get. I hope that helps Philip Posted by Philip 26/09/2018 10:49:07