What kinda power can I expect from a 4bbl swap?

[XXSpiralXX]

    My 72 has a 2 bbl and is completely bone stock. I want to open up the exhaust a bit and maybe add a carb spacer. How much with this wake the motor up? It takes off real well for a 2 bbl and a small engine. This is only for now till I can get something else together as a daily driver.

[Chryco Psycho]

what size engine ?

[Ghoste]

If the cam and cylinders are worn, it may not be an increase in power at all.  It could even have to opposite effect.  Kind of like putting a Dominator on a 273.  Maybe not that extreme but the same principles at work.