Gdays,
I've got a 351 Clevo in a 1979 F350 with 90,000km's on it and need to know what's a good oil to run? I bought some Mobil1 20w50 but am starting too think it might be a little bit too thick?
Also how many litres do they take?

Cheers guys,
Alex

20W 50 is right for a Clevo. Its what I have run in all of mine.
I always found that the couple of times I used Mobil 1 in my 351's that they absolutley ate it.
I always used a good quality mineral oil. Changing it frequently (every 5000km) is more important then how good the oil is in my opinion.

As above, only use mineral oil!!

clevos are no good with synthetic oils.