Re: 2.9 rebuild project.
The MAP/SD computer system can handle small cam changes. Anything too much and you'll have to switch over to a MAF computer to measure actual air flow as opposed to engine vacuum.
Boring is generally for restoring worn out cylinder walls as opposed to a performance upgrade on an engine with this little displacement. The money involved is not worth the return from a performance perspective.
Lots to a cam than just bigger, or higher lobes. Overlap, duration, etc all important factors on what cam will work best for how it needs to perform. Ask yourself what you want, then ask around some different cam manufacturers if they can grind it and work with them on a grind that will work best for your application.
If I had to do it all over again, I would start my build with having 2.8L flat top pistons installed (boring required and maybe some modifications). Mid/high RPM cam with matching valve springs, will have to figure out your new compression ratio. World heads ported with valve work and matched intakes. ARP rod bolts installed in the rods. Aluminum rocker arm spacers. Would try to find a way to do 1.5:1 or 1.6:1 rockers, but may not be feasible. Camcraft did make roller tip 1.55:1 roller rockers, but not sure if they still sell them ($500). Either way, you're looking at A LOT of money to get significant gains.
1987 Ford Ranger Short Bed 5.0L/T-5 Project
1988 Ford Ranger Long Bed Parts Truck
1993 Ford Tempo 2.3L OHV HSC Auto - D/D Stock.
1999 Honda Accord VTEC Auto
2002 Dodge Caravan - 3.3L Auto