I know that when converting a series to v8 a remote is necessary, as the filter goes the axle.
My 101 is currently a parts filling system, so I can't get to it.
Photos of pump? Not familiar with red top pumps. Do you use a swirl pot or tank? I suspect you might have a EFI pump. Get the standard RRC pump and see what happens.
Bear in mind this was done in a hurry as I had a ferry to catch. And I've discrete oil and charge coolers in front of the series radiator.
I cut away the horn mounting to get this to "work".
Er, is blanking the oil ports on the filter wise? There was a good article on here about eight years ago suggesting not. It effectively blocks the filter, iirc.
I can't remember exactly how much I took out. I'll take a photo in the morning if I remember.
Are you keeping the TDI oil cooler? Or series oil filter?
Seriously though. You've a brick with huge tyres and very low gearing using an engine designed when petrol was cheaper than water.
It's not going to be competitive with anything, bar a petrol HGV.
I think I got about 22mpg out of mine when we spent a week driving about France.
2.8 international engines tgv
Mostly motorway, rather than nipping down the shops.
I had to spend 17 euros on French diesel. The rest I took with me (cheap...