Larry Davidson is a very dependable supplier of accessories and materials for old-timer and vintage flying. He's located in Virginia, USA. His main speciality is the supply of components for spark ignition operation, including a variety of state-of-the-art transistorized ignition support systems, high-quality Rimfire spark plugs, Larry's own light and efficient coils and high tension leads. However, he also sells such items as dethermalizer fuse, D/T timers, Polyspan covering material, Polyspan colour dyes, fuelling syringes, etc. In addition, he stocks some BMJR laser kits. I've found his products to be of the very highest quality.
Larry's current catalogue can be viewed here. Since prices and stock can change without notice, it's best to contact Larry directly at firstname.lastname@example.org to inquire about your needs and also to learn the postage costs.
A detailed article about spark ignition engine operation is currently in preparation, based on my own application of a number of Larry's fine products.