Hi,
I agree a spin-on filter adapter is very useful. I've got one on my TR4, where it also serves the oil cooler take-off.
Be aware there were several different filter heads used on TRs over the years. They have different threads and require different adapters, so check the side of the head for a label (Pur-O-Later on my TR4) and talk to someone knowledgeable like the folks at TRF, with your engine serial number close at hand.
/ubbthreads/images/graemlins/cheers.gif