289 head help.

[cleandan]

I am rebuilding the 289 for my Sunbeam Tiger..."the Cobra that wasn't". Because the space constraints are so very tight, I am finding it somewhat difficult to locate performance aftermarket heads that are exactly the same outer dimentions as Ford originals. I think the iron Windsor JR heads do fit this bill, but I have been unable to confirm that. Anyway, my goal for the 289 is a pump gas motor that makes good torque (relative I know) does not require massive cooling, and will be happy on the street, with occasional road track blasts.
My question is based on the flow of stock heads. If my 289 is built with a 62-6500 rpm red line, will the Windsor JR heads flow well enough out of the box for my limited small CI motor, or will porting them gain me enough to overcome the cost of porting?
If you are certain about any other heads, please let me know.
My limitations are exhaust port location, and valve cover rail height. I CAN NOT run taller than stock valve covers, and I do not want to make custom headers for exhaust ports that are not in the stock location. I have had MANY people tell me "they think" a million times. I, however, do not want to spend $1500-2000 on a set of heads based on a guesstimate. Thanks for the input and have a great day.