1929 Excelsior Super-X Hillclimber Back to contest Vote Description 1929 Excelsior Super-X Hillclimber One of 21 built, this twin-port 750cc (45 cubic inch) Super-X was powered by alcohol and benzol. Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Website Δ Share OK More