Hi Racer,
I hope you find the information is of help to you, you will find that avgas is available from some small airports, however you must understand that the calorific value of avgas is very different to pump gas. You would not be able to run anything like standard jetting as avgas is a slower burning fuel. You would in addition, to get it running well in your motor proberbly need to modify, compression ratio,& or squish.
Some oils that are used in conjuction with Avgas100/130 will not blend without adding between 5-15% of benzol, or toluol (methyl benzine) but Castrol R & Castrol A747 both blend.(IT is prooven that additions to Avgas will, without doubt, accelerate piston to bore wear)
Take a tip from an old racer, stay with shell opimax, get the compression ratio right for that fuel, take some time doing plug chops untill you get mixture correct, a good pair of chambers and have good reliable fun.
Regards,
David.