This thread got me looking more into the archives on the 7/4 swap.

One guy thought it was only an advantage if using a single plane intake and thought he lost power on a dual plane.

Another guy in the race section said he gained 15hp on a 700 hp build.

Cliff R said he has chosen not to try them because from all the Pontiac builders that have dyno'd them for street motors they found no benefit.

I think it was Tom Voight however was more open to them since he is a ford guy it is more of a ford firing order for the Windsor more (I think).

The two benefits that were highly debated was how the firing order effected the main bearings and how the firing order distributed the intake charge. I guess that would also effect the exhaust pulses as well.

I think someone said that Crane wanted an extra $100 for a 4/7 cam while some of the other like Lunati would do it for nothing.

Anyway you can read up on it by searching "4/7" in the archives.