Has anyone use a cam with 4/7 swap and seen any inprovement in horsepower

I don't think its worth much, in a street/strip combo. The only person that I know thats done it is Ed. Brian might have some data for you :confused:

I do not have one.

The one thing to remember about going after details like a 4-7 swap cam is that even the hard core guys only see a few hp from this. So on anything short of a max effort engine there will be no gain, only a thinner wallet.

Modern engines, like the GM LS series, were designed this way right from the start - because the old firing order was designed for the best operation of a carburated engine with a dual plane intake manifold vs. a fuel injected engine with an open plenum intake.

Thomas