The R heads unported should work great. I think on a 351 I saw that the R heads made 35hp more than the Street heats, so they should be well worth it.
Skyler
------------------
-1989 Saleen Mustang #406- TFS Heads, E-303, edelbrock intake,70MM TB, 73mm MAF, off road H, headers and 3chamber flows.
12.55@107mph
Runs on 87 Octane and gets 24mpg!