I'm not sure about a 409, but I know for sure there is a 408 stroker. Indy Mustang Performance has them. Two different kinds, 550 hp version or 575 hp version. Take your pick. Here's the URL.
http://indymustang.stangnet.com/index.html
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'69 Coupe with 351W
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Edelbrock RPM intake, Edelbrock RPM cam, Edelbrock 750 cfm carb, Edelbrock lifters, Edelbrock double roller timing chain, Edelbrock valve springs, Accel coil, Moroso Blue-Max wires, Hedman headers, 2 1/2" pipe, glasspacks, Flex fan, Lakewood traction bars, C4, 9" Currie on order, 290hp-stock heads
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The Surgeon General didn't say anything about smoking your azz!!