I have the INNOVA digital dial-back timing light. It works with the MSD ignition. Have a chrome dial back also, but the MSD messes it up.

https://www.amazon.com/INNOVA-5568-Pro-Timing-Light-Tool/dp/B000EVU8J8/ref=sr_1_1?ie=UTF8&qid=1523285360&sr=8-1&keywords=equus%2Btiming%2Blight&th=1