[302 LX Eric]

I haven't, but on a set of stock heads the exhaust can definitely use the extra bump to help rid the cylinder of all spent gases.

However, as Kell said, if you get a good cam for your application (proper duration, lobe separation, lift) and especially if you match this with a nice set of aftermarket heads (a la TFS TW, AFR, etc) you won't need to do the "mix match suffle."

E