Tyre Size on series three

Hi, I have a '78 series 3 swb parrabollic and want to fit disco 200 axles, could anyone tell me what the best size wheel & tyre I can get without cutting arches etc. I currently have 235;s on white 8 spokes but I am wanting bigger tyres. I understand the axles are wider too.
I am fitting the parabollics to the new axles and know the track rod will be a pain has anyone modyfied this before??

its more of a pain than its worth, i looked into it but i decided not to on the basis its not worth it
if its the disk brakes you are after get a rocky mountain kit its a lot less hassle and makes a better job of it

as for tyres 750R16s look best on a series

7.50R16, 235/85R16, 265/70R16. anything bigger and you'll be out with the angle grinder.

I've got 9.00x16 or 255/100R16 and cutting is required, front not back.