Although I have a low deck stroker(470 ci.), going from ported 906`s to "Thumper" ported rpm`s took me from 10.40`s to 9.79 (so far) but I also went from a solid to a roller. Point is they will work well w/a valve touch up and some light bowl work and clean up in your case. Just did a 2 circuit carb conversion for a friends 470 BB Ferd and ported/converted his E-brock clover leaf manifold into a nice generous standard open plenum and SHOULD take him from his 10.08 best into the 9`s no problem then he`s gonna let me work over his E-brock for even more power. I like the challenge of using a stock replacement head and going faster that some "high dollar" stuff.................fun, fun fun.