Anyone know how tight to tighten the ancillary belt on a classic gc8 and what type pressure I should have on front and rear

Cheers

Which belt ? The alternator one or are you on about something else ?

If alternator look in front of it between the rad and block you'll see a long bolt pointing down, just tighten that until you can just flex the belt with your thumb a little,

As for tyres I think it's around 32 front 30 back but unsure