Oil change

[Stevo302]

Sorry if this is a repeated question.

What oil and filter would be recommended for my 1971 Vixen 2500? But note my car has a engine out of a 1974 2500TC, it was changed years ago back in the 80's for reasons I don't know.
Book says Castrol GTX, SAE 20/W50.

Rimmer Bros for the bits? Something like this?
https://rimmerbros.com/Item--i-RX1363

Thank you.

[plasticpig1972]

On my Classic cars i use Castrol GTX or similar .
I don't see the point of putting Synthetic Oils in an Engine that weren't designed for them.
I change the Oil around every 3000 or 4000 miles + Filter of course.
Alan

[TVR by BVR]

Since the engine in your vehicle is a flat tappet engine and the camshaft is splash lubricated is it very importend that you use an engine oil with the right amount of ZDDP (zinc) it should carry at least 1200ppm, the reason for this is that the zinc leaves a small layer of wear protector on all the metals it comes in contact with and therefore it prevents metal to metal contact and it saves your engine.
Modern oils were designed for modern engines not the engine in your vehicle, there are several oil companies that produce engine oils for the older engines, I use Penrite oil in all my classic cars and with good results.