1. single grade 30 classic oil without detergents or 20 if you drive in winter .
2. regular as long as you havent raised the compression, no additives needed.
3. you must get a oil filter if you use modern oil (get a Frantz toilet paper Filter if you want your oil staying clean but at least a regular bypass filter).
The "vintage" oil had no detergents so the slush stayed (mostly) on the bottom of the pan.
Modern oil for modern cars with filters has to transport the slush to the filter so it has detergents that keep the particles in suspension.
If you have no filter they go straight to your bearings.
Those cast iron wonders forgive a lot so you wont ruin it with the wrong oil (lots of guys here drive modern oil without filter) but for me it is always a peace of mind having the slush filtered out.
Don`t rev it to much if cold, drive moderate till ist is warm.
And here comes the most important one:
HAVE FUN!
Frank
