You know what they say,, 1 Mans Junk is another Mans Treasure,,
With a large tank like that it was most likely set up for Endurance Racing where you race for a set amount of Time, Not a set number of laps, Not everybody races like we do here in the US. I believe there are Endurance classes in both IMPBA and NAMBA but not many run them.

SJN You have a lot of work ahead of you to get that thing Screaming Again, it's a shame he left it out like that,, Must not have been something HE Built,,[:-][]
You may be able to get it going enough to get that thing up on a good plain without many parts,, But I would bet money it won't do it for long, and it will most likely destroy a lot more the next time it goes. If your serious about getting that thing Screamin Again and not just On Plane you would be better off replacing the bearings, Piston, and Sleeve,,, Before it destroys the rest of the engine and makes it a good paper weight for your desk.