Any engine we sell 3 times a year or more we either keep in inventory or on our production schedule for faster response. For other applications we may have a core in inventory available to build. The average lead time for an engine to replace a stock application is between 4-6 weeks. An engine with special modifications (A large percentage of what we build) will take longer. Hi Performance, Restoration, Industrial, Antique Auto & Antique Marine will be quoted after evaluation and consultation with the customer.