You don't mention what the engine is in, but you could try the 'oil finder' section at Opie Oils website, or phone them for recommendations - they're very approachable and helpful
http://www.opieoils.co.uk/c-337-cars.aspx
The best you can afford!
No one's suggesting a mineral oil for running in? If it's been rebuilt with replacement wearing parts it's what I'd do.
Something dirt cheap for initial startup/checking over. Then a single grade mineral oil for running in (however you choose to to run it in).
Then a multi grade fully synthetic (if cost is not an issue) for normal running. Not too thin though, maybe 10w60.
If you're disregarding price, in a clean engine, there no reason not to run synthetic. Better not try to extend oil change intervals with it though, an old, carbbed engine will put lots of curious stuff into the oil that ought to be dumped out fairly regularly.
It's got 30w dinosaur oil at the moment to run it in, that will get changed <500miles.
As I under stand it a fully synthetic oil would be the way to go, bearing in mind it's had a full flow oil mod carried out, for spin-on filters
Oil is cheap in comparison to parts. Was thinking of Mobil 1 [the fact I can get it rather cheap has nothing to do with it]
Seemingly a lot of the modern oils have massively reduced ZDDP content due to diff engine designs which don't need it, but seemingly older engines needed the ZDDP to cut down on wear, you can add it in, but too much or too little causes wear, so its often just easier to buy an oil with it already in the oil.
On the mobil oil containers some wheres is a tech dept for phone help, I phoned these guys re my truck, the oil (theirs) I was going to use was totally wrong, he checked on his tech spec type of engine/tolerances etc and went on to recomend a differant one, used it and had absolutely no problems, my advice find that tech. dept phone no. and give them a call. As why risk cocking up a proper re build.......Arther (google might have the no.)It's got 30w dinosaur oil at the moment to run it in, that will get changed <500miles.
As I under stand it a fully synthetic oil would be the way to go, bearing in mind it's had a full flow oil mod carried out, for spin-on filters
Oil is cheap in comparison to parts. Was thinking of Mobil 1 [the fact I can get it rather cheap has nothing to do with it]